[gentoo-user] Clock is way off

[gentoo-user] Clock is way off

[Grant]

Hello, the time on my laptop is off by a number of hours although I
have /etc/conf.d/clock set up to exactly match that of my router, and
the router has the correct time.  I have this in /etc/conf.d/clock:

CLOCK="UTC"
TIMEZONE="US/Pacific"

'date' says 'Local time zone must be set--see zic manual page' but I'm
confused by the zic man page.  Do I need to run a zic command to
correct this?  If so, would it be something like this:

zic -l US/Pacific

- Grant
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Re: [gentoo-user] Clock is way off

[AJ Spagnoletti]

>
> CLOCK="UTC"
> TIMEZONE="US/Pacific"

If the clock is off by 8 hours from the time it is supposed to be (I
think thats what pacific time zone is I could be wrong) you can try
changing CLOCK="local"

AJ
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[gentoo-user] Re: Clock is way off

[Anno v. Heimburg]

Grant wrote:

> CLOCK="UTC"
> TIMEZONE="US/Pacific"

That looks fine.

Do you dual-boot with Windows? In this case, set CLOCK="local". If not,
something else is amiss.

Where does /etc/localtime point? Is it consistent with the entry in 
/etc/conf.d/clock?

HTH,
Anno.



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Re: [gentoo-user] Re: Clock is way off

[Grant]

> > CLOCK="UTC"
> > TIMEZONE="US/Pacific"
>
> That looks fine.
>
> Do you dual-boot with Windows? In this case, set CLOCK="local". If not,
> something else is amiss.

Gentoo only. :)

> Where does /etc/localtime point? Is it consistent with the entry in
> /etc/conf.d/clock?

I have:

-rw-r--r-- 1 root root 255 Apr 25 20:58 /etc/localtime

on the laptop with the incorrect time, and the router with the correct time.

- Grant
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Re: [gentoo-user] Re: Clock is way off

[Neil Bothwick]

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On Wed, 9 May 2007 14:27:52 +0000, Grant wrote:

> I have:
> 
> -rw-r--r-- 1 root root 255 Apr 25 20:58 /etc/localtime
> 
> on the laptop with the incorrect time, and the router with the correct
> time.

That only tells us that /etc/localtime is a file, not which timezone data
it contains. Re-emerging timezone-data will ensure that it has the data
for the timezone you specified in /etc/conf.d/clock.

Setting the timezone in /etc/conf.d/clock has no effect until you next
emerge timezone-data. A 255 byte /etc/localtime is probably either Factory
or localtime, i.e. nothing has been set.


-- 
Neil Bothwick

Irritable? Who the bloody hell are you calling irritable?

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Re: [gentoo-user] Re: Clock is way off

[Grant]

> > I have:
> >
> > -rw-r--r-- 1 root root 255 Apr 25 20:58 /etc/localtime
> >
> > on the laptop with the incorrect time, and the router with the correct
> > time.
>
> That only tells us that /etc/localtime is a file, not which timezone data
> it contains. Re-emerging timezone-data will ensure that it has the data
> for the timezone you specified in /etc/conf.d/clock.
>
> Setting the timezone in /etc/conf.d/clock has no effect until you next
> emerge timezone-data. A 255 byte /etc/localtime is probably either Factory
> or localtime, i.e. nothing has been set.

Just what I needed.  Thanks Neil.

- Grant
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Re: [gentoo-user] Re: Clock is way off

[Redouane Boumghar]

Hello everyone,

I recently had to reset my clock to a more "correct" (that may be subjective) setting.
In your case I would set my /etc/conf.d/clock file as:

CLOCK="UTC"
TIMEZONE="US/Pacific" 

then I would assure that my /etc/localtime file is correct with the next command:

$ cp  /usr/share/zoneinfo/US/Pacific /etc/localtime

If you have no zoneinfo files then consider emerging 'timezone-data'.
The setting like that should be fine and if you have an offset it's that your hardware clock
must be set to a time that is considered as UTC (since you have "CLOCK=UTC" in your conf)
while it's not.

So set your clock correctly  with rdate, ntp whatever...
and then write your system clock to your hardware clock (I guess this action is done at shut down).
You may use the following command :

$ hwclock --systohc

Then your machine is ready to have correct time as UTC. Be sure to have your profile
environnement variable TZ to be set to your timezone. In your .profile :

export TZ="US/Pacific";

Concerning dual boot.. as I am in !! Everywhere I could see advice to set my CLOCK var to "local"
but that's always a mess with the timezone... so the simple thing is to deactivate the Microsoft Windows
update or at least to set it to UTC time..
Thus keeping CLOCK="UTC" which would be a quite good standard.
But I understand Gentoo is installed to cause no harm to Windows, thats why there is this CLOCK="local" attitude
I guess.

Hope that helps
I'd be happy to share the pros and the cons...

-- 
Redouane BOUMGHAR
Physics, Remote Sensing and Digital Imagery Engineer

Neil Bothwick wrote:
> On Wed, 9 May 2007 14:27:52 +0000, Grant wrote:
> 
>> I have:
>>
>> -rw-r--r-- 1 root root 255 Apr 25 20:58 /etc/localtime
>>
>> on the laptop with the incorrect time, and the router with the correct
>> time.
> 
> That only tells us that /etc/localtime is a file, not which timezone data
> it contains. Re-emerging timezone-data will ensure that it has the data
> for the timezone you specified in /etc/conf.d/clock.
> 
> Setting the timezone in /etc/conf.d/clock has no effect until you next
> emerge timezone-data. A 255 byte /etc/localtime is probably either Factory
> or localtime, i.e. nothing has been set.
> 
> 

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Re: [gentoo-user] Re: Clock is way off

[Dale]

Redouane Boumghar wrote:
> Hello everyone,
>
> I recently had to reset my clock to a more "correct" (that may be
> subjective) setting.
> In your case I would set my /etc/conf.d/clock file as:
>
> CLOCK="UTC"
> TIMEZONE="US/Pacific"
> then I would assure that my /etc/localtime file is correct with the
> next command:
>
> $ cp  /usr/share/zoneinfo/US/Pacific /etc/localtime
>
> <snip>
> Hope that helps
> I'd be happy to share the pros and the cons...
>

I think you are supposed to link that localtime file instead of
copying.  If the file in zoneinfo gets updated then the one in /etc will
still be the old one.

Someone correct me if I am wrong here.

Dale

:-) :-)  :-)

-- 
www.myspace.com/-remove-me-dalek1967

Copy n paste then remove the -remove-me- part.

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Re: [gentoo-user] Re: Clock is way off

[Uwe Thiem]

On 09 May 2007, Dale wrote:
> Redouane Boumghar wrote:
> > Hello everyone,
> >
> > I recently had to reset my clock to a more "correct" (that may be
> > subjective) setting.
> > In your case I would set my /etc/conf.d/clock file as:
> >
> > CLOCK="UTC"
> > TIMEZONE="US/Pacific"
> > then I would assure that my /etc/localtime file is correct with the
> > next command:
> >
> > $ cp  /usr/share/zoneinfo/US/Pacific /etc/localtime
> >
> > <snip>
> > Hope that helps
> > I'd be happy to share the pros and the cons...
>
> I think you are supposed to link that localtime file instead of
> copying.  If the file in zoneinfo gets updated then the one in /etc will
> still be the old one.
>
> Someone correct me if I am wrong here.

Either way is possible. I prefer a link so I can see what /etc/localtime 
points to.

Uwe

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Re: [gentoo-user] Re: Clock is way off

[Neil Bothwick]

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On Wed, 09 May 2007 12:05:05 -0500, Dale wrote:

> I think you are supposed to link that localtime file instead of
> copying.  If the file in zoneinfo gets updated then the one in /etc will
> still be the old one.

You are not supposed to link it any more, because that will break if /usr
has not yet been mounted. Set the correct timezone in /etc/conf.d/clock
and portage will copy the correct file to /etc/localtime whenever you
update timezone-data.

> Someone correct me if I am wrong here.

Done ;-)


-- 
Neil Bothwick

Press every key to continue.

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[gentoo-user] Separate /usr [was: Clock is way off]

[Benno Schulenberg]

Neil Bothwick wrote:
> On Wed, 09 May 2007 12:05:05 -0500, Dale wrote:
> > I think you are supposed to link that localtime file instead of
> > copying.  If the file in zoneinfo gets updated then the one in
> > /etc will still be the old one.
>
> You are not supposed to link it any more, because that will break
> if /usr has not yet been mounted.

Are there (still) people who have /usr on a separate partition?  
And if so, why?

I only have /home and /usr/portage on separate partitions, 
everything else is on /, even /boot.

Benno
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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Neil Bothwick]

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On Wed, 09 May 2007 19:53:08 +0200, Benno Schulenberg wrote:

> > You are not supposed to link it any more, because that will break
> > if /usr has not yet been mounted.  
> 
> Are there (still) people who have /usr on a separate partition?  
> And if so, why?

I do, because everything but / and /boot is on LVM.

Even if you don't have a separate /usr, the current method is far easier
to maintain because your timezone is set in one of the standard
configuration files rather than a symlink somewhere else.


-- 
Neil Bothwick

"I am Homer of the Borg. You will be assim.... Hmm... Donuts..."

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Randy Barlow]

Benno Schulenberg wrote:
> Are there (still) people who have /usr on a separate partition?  
> And if so, why?
>
> I only have /home and /usr/portage on separate partitions, 
> everything else is on /, even /boot.

I have /usr on a separate lvm device just so I can shift around drive 
space (my gentoo machine is an older machine with not a ton of HD space, 
so the ability to change the sizes of different volumes is great!)

R
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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Albert Hopkins]

On Wed, 2007-05-09 at 19:53 +0200, Benno Schulenberg wrote:
> Are there (still) people who have /usr on a separate partition?  
> And if so, why? 

Because if you've got a lab full of similarly-configured workstations or
a forward-facing cluster of load-balancing servers, it may be more
convenient to have them all mount /usr, /home, etc. from a
centrally-managed file server.

--
Albert W. Hopkins

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Daniel Iliev]

On Wed, 09 May 2007 19:53:08 +0200
Benno Schulenberg <benno.schulenberg@gmail.com> wrote:

> 
> Are there (still) people who have /usr on a separate partition?  
> And if so, why?
> 

Yes, I'm one of those. 
Some say it gives performance boost (I'm not sure about it), but more
importantly it gives (partial) protection from file system damage. How
come? The partitions with most frequent writes are those
containing /var /home and /tmp. In case of power failure or system
lock-up the chances are better that a file system not taking writes at
the moment would survive the crash. Following this logic and since /usr
contains most of the programs and /bin & /sbin contain most of the
basic OS, those should reside on partitions with rare writes.


-- 
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Daniel

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Neil Bothwick]

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Hello Daniel Iliev,

> Some say it gives performance boost (I'm not sure about it), but more
> importantly it gives (partial) protection from file system damage. How
> come? The partitions with most frequent writes are those
> containing /var /home and /tmp. In case of power failure or system
> lock-up the chances are better that a file system not taking writes at
> the moment would survive the crash. Following this logic and since /usr
> contains most of the programs and /bin & /sbin contain most of the
> basic OS, those should reside on partitions with rare writes.

You could also argue that /usr needs the least protection from filesystem
damage, because it contains no data. /usr can be repaired with
a reinstall, unlike /var, /home or /etc.


-- 
Neil Bothwick

"They that can give up essential liberty to obtain a little
temporary safety, deserve neither liberty nor safety."
    Benjamin Franklin

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Daniel Iliev]

On Wed, 9 May 2007 21:03:58 +0100
Neil Bothwick <neil@digimed.co.uk> wrote:

> Hello Daniel Iliev,
> 
> > Some say it gives performance boost (I'm not sure about it), but
> > more importantly it gives (partial) protection from file system
> > damage. How come? The partitions with most frequent writes are those
> > containing /var /home and /tmp. In case of power failure or system
> > lock-up the chances are better that a file system not taking writes
> > at the moment would survive the crash. Following this logic and
> > since /usr contains most of the programs and /bin & /sbin contain
> > most of the basic OS, those should reside on partitions with rare
> > writes.
> 
> You could also argue that /usr needs the least protection from
> filesystem damage, because it contains no data. /usr can be repaired
> with a reinstall, unlike /var, /home or /etc.
> 
> 


That's a good point.

Only for the sake of arguing: those need no FS protection, but
recent back-ups :)



-- 
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Daniel

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Neil Bothwick]

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On Thu, 10 May 2007 00:21:06 +0300, Daniel Iliev wrote:

> > You could also argue that /usr needs the least protection from
> > filesystem damage, because it contains no data. /usr can be repaired
> > with a reinstall, unlike /var, /home or /etc.

> That's a good point.
> 
> Only for the sake of arguing: those need no FS protection, but
> recent back-ups :)

Recent is never recent enough. I used to think daily backups were fine,
until a failure at 5pm cost me a day's work :(


-- 
Neil Bothwick

Forget the Joneses...I can't keep up with The Simpsons.

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Naga]

On Wednesday 09 May 2007 23.37.58 Neil Bothwick wrote:
> Recent is never recent enough. I used to think daily backups were fine,
> until a failure at 5pm cost me a day's work :(

Once an hour synced across 3 computers, with a master copy made daily :)
-- 
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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Neil Bothwick]

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Hello Naga,

> > Recent is never recent enough. I used to think daily backups were
> > fine, until a failure at 5pm cost me a day's work :(  
> 
> Once an hour synced across 3 computers, with a master copy made daily :)

Two separate backup methods, run alternate hours (in case one of them
corrupts the backup) with an off-site backup to my Strongspace account
three times a day.

Belt, braces and string :)


-- 
Neil Bothwick

A friend in need may turn out to be a nuisance.

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Boyd Stephen Smith Jr.]

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On Wednesday 09 May 2007, Neil Bothwick <neil@digimed.co.uk> wrote 
about 'Re: [gentoo-user] Separate /usr  [was: Clock is way off]':
> Hello Daniel Iliev,
>
> > Some say it gives performance boost (I'm not sure about it), but more
> > importantly it gives (partial) protection from file system damage.
>
> You could also argue that /usr needs the least protection from
> filesystem damage, because it contains no data. /usr can be repaired
> with
> a reinstall, unlike /var, /home or /etc.

That's my view, which is why /usr (fast, RAID0) is separate from / 
(containing /etc; RAID6) on my machine.

-- 
Boyd Stephen Smith Jr.                     ,= ,-_-. =. 
bss03@volumehost.net                      ((_/)o o(\_))
ICQ: 514984 YM/AIM: DaTwinkDaddy           `-'(. .)`-' 
http://iguanasuicide.org/                      \_/     

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Mick]

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On Wednesday 09 May 2007 22:22, Boyd Stephen Smith Jr. wrote:
> On Wednesday 09 May 2007, Neil Bothwick <neil@digimed.co.uk> wrote
>
> about 'Re: [gentoo-user] Separate /usr  [was: Clock is way off]':
> > Hello Daniel Iliev,
> >
> > > Some say it gives performance boost (I'm not sure about it), but more
> > > importantly it gives (partial) protection from file system damage.
> >
> > You could also argue that /usr needs the least protection from
> > filesystem damage, because it contains no data. /usr can be repaired
> > with
> > a reinstall, unlike /var, /home or /etc.
>
> That's my view, which is why /usr (fast, RAID0) is separate from /
> (containing /etc; RAID6) on my machine.

These days I keep /usr/portage on a separate partition to minimise fs 
fragmentation.  On an old slooow box of mine I have /usr/local/bin 
and /usr/local/lib on separate disks, as well as /var/tmp and /usr/bin and 
keep them on primary partitions for extra speed and parallel 
access/processing across two different IDE controllers:

http://tldp.org/HOWTO/Multi-Disk-HOWTO.html

One can get really silly at this, I certainly did, but on modern machines with 
SATA drives the difference in speed is probably marginal.  I didn't keep 
notes of any benchmarks but despite the asthmatic hardware my 
multi-disk/partitioning scheme did pay some noticeable dividends as far as I 
can recall.  Of course, YMMV.
-- 
Regards,
Mick

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[darren kirby]

quoth the Benno Schulenberg:
> Neil Bothwick wrote:
> > On Wed, 09 May 2007 12:05:05 -0500, Dale wrote:
> > > I think you are supposed to link that localtime file instead of
> > > copying.  If the file in zoneinfo gets updated then the one in
> > > /etc will still be the old one.
> >
> > You are not supposed to link it any more, because that will break
> > if /usr has not yet been mounted.
>
> Are there (still) people who have /usr on a separate partition?
> And if so, why?

I have heard you can use a separate /usr to enhance security by mounting it 
readonly under normal circumstances. This way, bad guys can't mess with your 
binaries in /usr/bin and /usr/sbin, though it seems to me if they have access 
to mess with your /usr they can mess with anything anyway so...

I do have a separate /usr, but do not mount it readonly, as I --sync enough to 
make remounting it daily rather annoying.

> I only have /home and /usr/portage on separate partitions,
> everything else is on /, even /boot.
>
> Benno

-d
-- 
darren kirby :: Part of the problem since 1976 :: http://badcomputer.org
"...the number of UNIX installations has grown to 10, with more expected..."
- Dennis Ritchie and Ken Thompson, June 1972
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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Bo Ørsted Andresen]

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On Wednesday 09 May 2007 23:49:45 darren kirby wrote:
> I do have a separate /usr, but do not mount it readonly, as I --sync enough
> to make remounting it daily rather annoying.

Congratulations! You've just explained why PORTDIR defaulting to /usr/portage 
is stupid. The logical location for the tree would be on /var ... :)

-- 
Bo Andresen

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Neil Bothwick]

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On Thu, 10 May 2007 01:01:32 +0200, Bo Ørsted Andresen wrote:

> > I do have a separate /usr, but do not mount it readonly, as I --sync
> > enough to make remounting it daily rather annoying.  
> 
> Congratulations! You've just explained why PORTDIR defaulting
> to /usr/portage is stupid. The logical location for the tree would be
> on /var ... :)

Except that running emerge --sync without following it with emerge
--update is rather pointless, and that would require /usr to be mounted
rw wherever $PORTDIR was.

I do agree that /var is a far more logical location.


-- 
Neil Bothwick

Top Oxymorons Number 26: Software documentation

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Aleksandar L. Dimitrov]

On Thu, 2007-05-10 at 01:01 +0200, Bo Ørsted Andresen wrote:
> On Wednesday 09 May 2007 23:49:45 darren kirby wrote:
> > I do have a separate /usr, but do not mount it readonly, as I --sync enough
> > to make remounting it daily rather annoying.
> 
> Congratulations! You've just explained why PORTDIR defaulting to /usr/portage 
> is stupid. The logical location for the tree would be on /var ... :)
> 

I think the original reason for this is that FreeBSD ports is also
in /usr/ports. FS-optimization freaks (like myself) can always generate
a sparse file and/or mount /usr/portage somewhere else. A script that
does the update after this (w/ remounting and the like) is no big
magic. 

Regards, Aleks

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Alan McKinnon]

On Thursday 10 May 2007, Bo Ørsted Andresen wrote:
> On Wednesday 09 May 2007 23:49:45 darren kirby wrote:
> > I do have a separate /usr, but do not mount it readonly, as I
> > --sync enough to make remounting it daily rather annoying.
>
> Congratulations! You've just explained why PORTDIR defaulting to
> /usr/portage is stupid. The logical location for the tree would be on
> /var ... :)

You are perfectly correct. That's why I have:

alan@nazgul ~ $ mount | grep /var
/dev/mapper/vg-var on /var type reiserfs (rw,noatime,notail)
/dev/mapper/vg-portage on /var/portage type reiserfs (rw,noatime)
/dev/mapper/vg-distfiles on /var/distfiles type reiserfs 
(rw,noatime,notail)

Note that distfiles is not a sub-dir of portage either

-- 
Optimists say the glass is half full,
Pessimists say the glass is half empty,
Developers say wtf is the glass twice as big as it needs to be?

Alan McKinnon
alan at linuxholdings dot co dot za
+27 82, double three seven, one nine three five
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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Neil Bothwick]

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On Wed, 09 May 2007 15:49:45 -0600, darren kirby wrote:

> I have heard you can use a separate /usr to enhance security by
> mounting it readonly under normal circumstances. This way, bad guys
> can't mess with your binaries in /usr/bin and /usr/sbin,

Instead of only being able to get at the really important stuff in /bin
and /sbin?

> I do have a separate /usr, but do not mount it readonly, as I --sync
> enough to make remounting it daily rather annoying.

1) Use a script to remount /usr, sysnc, remount /usr

2) Much better, use a separate filesystem for /usr/portage (or put it
   on /var)

3) Better still,
http://gentoo-wiki.com/TIP_Speeding_up_portage#Make_A_Sparse_File_to_create_portage_in


-- 
Neil Bothwick

"One World, One Web, One Program" - Microsoft Promotional Ad
"Ein Volk, Ein Reich, Ein Fuhrer" - Adolf Hitler

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[darren kirby]

quoth the Neil Bothwick:
> On Wed, 09 May 2007 15:49:45 -0600, darren kirby wrote:
> > I have heard you can use a separate /usr to enhance security by
> > mounting it readonly under normal circumstances. This way, bad guys
> > can't mess with your binaries in /usr/bin and /usr/sbin,
>
> Instead of only being able to get at the really important stuff in /bin
> and /sbin?

Well, very nice how you trimmed the part of my original email that speaks to 
your question and makes the same point as you, but thanks for making me look 
stupid anyway...

Yeah, I know, I make myself look stupid, right ;)

-d
-- 
darren kirby :: Part of the problem since 1976 :: http://badcomputer.org
"...the number of UNIX installations has grown to 10, with more expected..."
- Dennis Ritchie and Ken Thompson, June 1972
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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Neil Bothwick]

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On Wed, 09 May 2007 18:31:07 -0600, darren kirby wrote:

> quoth the Neil Bothwick:
> > On Wed, 09 May 2007 15:49:45 -0600, darren kirby wrote:  
> > > I have heard you can use a separate /usr to enhance security by
> > > mounting it readonly under normal circumstances. This way, bad guys
> > > can't mess with your binaries in /usr/bin and /usr/sbin,  
> >
> > Instead of only being able to get at the really important stuff
> > in /bin and /sbin?  
> 
> Well, very nice how you trimmed the part of my original email that
> speaks to your question and makes the same point as you, but thanks for
> making me look stupid anyway...

The part I trimmed was "though it seems to me if they have access 
to mess with your /usr they can mess with anything anyway so..." which I
guess could mean what you say you meant rather than how I read it. Sorry
if you think I twisted your post, that wasn't my intention.


-- 
Neil Bothwick

Remember that the Titanic was built by experts, and the Ark by a newbie

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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[darren kirby]

quoth the Neil Bothwick:

> The part I trimmed was "though it seems to me if they have access
> to mess with your /usr they can mess with anything anyway so..." which I
> guess could mean what you say you meant rather than how I read it. Sorry
> if you think I twisted your post, that wasn't my intention.

It's cool, I just thought it was funny ;)
-d
-- 
darren kirby :: Part of the problem since 1976 :: http://badcomputer.org
"...the number of UNIX installations has grown to 10, with more expected..."
- Dennis Ritchie and Ken Thompson, June 1972
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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Alan McKinnon]

On Thursday 10 May 2007, Neil Bothwick wrote:
> 3) Better still,
> http://gentoo-wiki.com/TIP_Speeding_up_portage#Make_A_Sparse_File_to_
>create_portage_in

I never understood why portage on a sparse file is beneficial. Mine is 
on a small reiser logival volume mounted with option "tail". It's just 
big enough to hold portage with 10-15% free space (the tree doesn't 
expand that much over time).

Care to elabortae on the benfits you get doing it your way?

-- 
Optimists say the glass is half full,
Pessimists say the glass is half empty,
Developers say wtf is the glass twice as big as it needs to be?

Alan McKinnon
alan at linuxholdings dot co dot za
+27 82, double three seven, one nine three five
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Re: [gentoo-user] Separate /usr [was: Clock is way off]

[Neil Bothwick]

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Hello Alan McKinnon,

> I never understood why portage on a sparse file is beneficial. Mine is 
> on a small reiser logival volume mounted with option "tail". It's just 
> big enough to hold portage with 10-15% free space (the tree doesn't 
> expand that much over time).

It is faster. If I were going to use reiserfs (I use ext2 for this) I'd
use it with notail, the tail packing impacts performance. I'm more
interested in speed than saving disk space.


-- 
Neil Bothwick

We shall shortly be landing. Please return your stewardess to
the upright position.

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[gentoo-user] Re: Separate /usr

[Alexander Skwar]

Neil Bothwick <neil@digimed.co.uk> wrote:

> Hello Alan McKinnon,
> 
>> I never understood why portage on a sparse file is beneficial. Mine is
>> on a small reiser logival volume mounted with option "tail". It's just
>> big enough to hold portage with 10-15% free space (the tree doesn't
>> expand that much over time).
> 
> It is faster.

Hm. I don't understand. Why is portage in a sparse file of, let's say, 
400m, with reiserfs and notail mounted, faster, then a real partition
of 400m with reiserfs and notail?

What makes the sparse file faster?

Alexander Skwar

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Re: [gentoo-user] Re: Separate /usr

[Neil Bothwick]

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On Thu, 10 May 2007 10:41:04 +0200, Alexander Skwar wrote:

> > It is faster.  
> 
> Hm. I don't understand. Why is portage in a sparse file of, let's say, 
> 400m, with reiserfs and notail mounted, faster, then a real partition
> of 400m with reiserfs and notail?

No idea, but I tried it when I encountered that page and portage
operations were measurably faster.


-- 
Neil Bothwick

If you got the words it does not mean you got the knowledge.

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Re: [gentoo-user] Re: Separate /usr

[Benno Schulenberg]

Neil Bothwick wrote:
> On Thu, 10 May 2007 10:41:04 +0200, Alexander Skwar wrote:
> > Hm. I don't understand. Why is portage in a sparse file of,
> > let's say, 400m, with reiserfs and notail mounted, faster, then
> > a real partition of 400m with reiserfs and notail?
>
> No idea, but I tried it when I encountered that page and portage
> operations were measurably faster.

That might well be just the transfer effect: you went from an old 
fragmented file system to a fresh unfragmented one.

Benno
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Re: [gentoo-user] Re: Separate /usr

[Neil Bothwick]

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On Thu, 10 May 2007 12:11:34 +0200, Benno Schulenberg wrote:

> > No idea, but I tried it when I encountered that page and portage
> > operations were measurably faster.  
> 
> That might well be just the transfer effect: you went from an old 
> fragmented file system to a fresh unfragmented one.

I allowed for that. I created a new filesystem for /usr/portage - I had
been using a directory in /usr before.


-- 
Neil Bothwick

"DOOM ", said Pooh, and Slaughtered Christopher Robin with a chainsaw

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Re: [gentoo-user] Re: Separate /usr

[Dan Farrell]

On Thu, 10 May 2007 11:34:46 +0100
Neil Bothwick <neil@digimed.co.uk> wrote:

> On Thu, 10 May 2007 12:11:34 +0200, Benno Schulenberg wrote:
> 
> > > No idea, but I tried it when I encountered that page and portage
> > > operations were measurably faster.  
> > 
> > That might well be just the transfer effect: you went from an old 
> > fragmented file system to a fresh unfragmented one.
> 
> I allowed for that. I created a new filesystem for /usr/portage - I
> had been using a directory in /usr before.
> 
> 
Well, maybe it has to do with the efficiency of reading discontiguous
blocks from one file as opposed to a filesystem.  Since it's a sparse
file, there might be a lot of 'space' that, if it were on an actual
disk, the heads would have to pass over; thus there may be a way in
which a sparse file is more efficient than a regular filesystem.  

Remeber that the files in portage are, except for distfiles, quite
small.  By my calculation, the average size for files and directories
under $PORTDIR (excluding $DISTDIR of course) is only 62 bytes.  What
would you bet that on a disk partition, the other 962 to 4034 bytes per
block (I couldn't have block sizes less than 1K on reiser for my
portage, and 4096 is the default for most FS's) are filled with
nothing, and the heads need to pass over them to read the next block.
On a sparse file that space is merely reserved, it needn't actually
exist.   Hope that helps you conceptualize the difference.
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Re: [gentoo-user] Re: Separate /usr

[Andrey Gerasimenko]

On Fri, 11 May 2007 01:36:03 +0400, Dan Farrell <dan@spore.ath.cx> wrote:

> On Thu, 10 May 2007 11:34:46 +0100
> Neil Bothwick <neil@digimed.co.uk> wrote:
>
>> On Thu, 10 May 2007 12:11:34 +0200, Benno Schulenberg wrote:
>>
>> > > No idea, but I tried it when I encountered that page and portage
>> > > operations were measurably faster.
>> >
>> > That might well be just the transfer effect: you went from an old
>> > fragmented file system to a fresh unfragmented one.
>>
>> I allowed for that. I created a new filesystem for /usr/portage - I
>> had been using a directory in /usr before.
>>
>>
> Well, maybe it has to do with the efficiency of reading discontiguous
> blocks from one file as opposed to a filesystem.  Since it's a sparse
> file, there might be a lot of 'space' that, if it were on an actual
> disk, the heads would have to pass over; thus there may be a way in
> which a sparse file is more efficient than a regular filesystem.
>
> Remeber that the files in portage are, except for distfiles, quite
> small.  By my calculation, the average size for files and directories
> under $PORTDIR (excluding $DISTDIR of course) is only 62 bytes.  What
> would you bet that on a disk partition, the other 962 to 4034 bytes per
> block (I couldn't have block sizes less than 1K on reiser for my
> portage, and 4096 is the default for most FS's) are filled with
> nothing, and the heads need to pass over them to read the next block.
> On a sparse file that space is merely reserved, it needn't actually
> exist.   Hope that helps you conceptualize the difference.

I guess the idea is correct, but the details are questionable. The heads  
do not move over empty tails, the spinning disk does. A head just moves to  
the track that contains the required sectors. The head movement and disk  
spinning do not influence performance directly since there are many levels  
of caching between a physical read and an application.

It looks like it takes much less buffer space to cache lots of small files  
when they are joined into a sparse file than when they are in a real file  
system, making sparse file very efficient.

-- 
Andrei Gerasimenko
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Re: [gentoo-user] Re: Clock is way off

[Dale]

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Neil Bothwick wrote:
> On Wed, 09 May 2007 12:05:05 -0500, Dale wrote:
>
>   
>> I think you are supposed to link that localtime file instead of
>> copying.  If the file in zoneinfo gets updated then the one in /etc will
>> still be the old one.
>>     
>
> You are not supposed to link it any more, because that will break if /usr
> has not yet been mounted. Set the correct timezone in /etc/conf.d/clock
> and portage will copy the correct file to /etc/localtime whenever you
> update timezone-data.
>
>   
>> Someone correct me if I am wrong here.
>>     
>
> Done ;-)
>
>
>   

Learn something every day.  Funny, it has been a long time since I had
to reinstall Linux.  It just runs and runs and runs and runs and runs
and runs and runs. . . . . .

I did check and it was changed to a regular file on mine too.  I guess
it did that itself during the update.  I don't remember doing it anyway.

Thanks for the correction.

Dale

:-)  :-)  :-)  :-)

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Copy n paste then remove the -remove-me- part.


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