[gentoo-amd64] OT: Need advice on usb thumb drive boot

[gentoo-amd64] OT: Need advice on usb thumb drive boot

[P.V.Anthony]

Hi,

I am going to build a filesever for my office. We are going to put in 15 
drives in the case. There will be 4gb of ram.

I was thinking of putting the OS on two thumbdrives raided as raid 1. 
The reason for this is so that I can dedicate all the 15 drives for data 
storage and there is no more space to place two additional drives for 
the OS.

 From the net, I gather that flash drives have a limited write/erase. Is 
there a way that this can be overcome?

I was thinking of aufs. From what I understand, with aufs all the write 
is done only once when we shutdown the server. In this way everything is 
in the ram until a sync command is sent. This way the flash drives will 
last longer. Is this correct?

I could also make a symbolic link for the /var and /tmp to the main drives.

Is there a better way? Please advice.

P.V.Anthony
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[gentoo-amd64] Re: OT: Need advice on usb thumb drive boot

[Duncan]

"P.V.Anthony" <pvantony@singnet.com.sg> posted
45E510B6.8060104@singnet.com.sg, excerpted below, on  Wed, 28 Feb 2007
13:18:46 +0800:

>  From the net, I gather that flash drives have a limited write/erase. Is
> there a way that this can be overcome?
> 
> I was thinking of aufs. From what I understand, with aufs all the write
> is done only once when we shutdown the server. In this way everything is
> in the ram until a sync command is sent. This way the flash drives will
> last longer. Is this correct?
> 
> I could also make a symbolic link for the /var and /tmp to the main
> drives.

With modern thumb drives it shouldn't matter that much.  They have a wear-
leveling write algorithm that spreads out the writes such that no one 
cell gets worn out significantly before the others, and such drives often 
last longer than regular drives now days.

I'd go ahead and symlink /var and /tmp to your regular drives and make 
sure swap (if any) is on the regular drives as well, but other than that, 
it shouldn't matter much.  Or... do what I did with my 8 gig of RAM, and 
run /tmp on tmpfs, with /var/tmp symlinked to it as well.  It definitely 
speeds up merges when all the temporary work files are in RAM based 
tmpfs! =8^)

If you want extra safety, use the RAID-1 as you suggested, but make sure 
the drives are two different manufacturers (if possible, make sure the 
FLASH comes from two different suppliers as well), thus avoiding two 
drives with such close characteristics that they die together.  If you 
want more safety than that, either expand it to a three-way RAID-1 or 
swap out one of the two for a new one in say 9 months, using the one 
that's swapped out for something else.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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Re: [gentoo-amd64] Re: OT: Need advice on usb thumb drive boot

[Boyd Stephen Smith Jr.]

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On Wednesday 28 February 2007, Duncan <1i5t5.duncan@cox.net> wrote 
about '[gentoo-amd64]  Re: OT: Need advice on usb thumb drive boot':
> "P.V.Anthony" <pvantony@singnet.com.sg> posted
> 45E510B6.8060104@singnet.com.sg, excerpted below, on  Wed, 28 Feb 2007
> 13:18:46 +0800:
> >  From the net, I gather that flash drives have a limited write/erase.
> > Is there a way that this can be overcome?
>
> With modern thumb drives it shouldn't matter that much.  They have a
> wear- leveling write algorithm that spreads out the writes such that no
> one cell gets worn out significantly before the others, and such drives
> often last longer than regular drives now days.

In addition, modern flash sectors can be written more than 100000 times.  
If all you were doing is writing to a single sector over and over, it 
would still take years to wear it out.

-- 
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