Re: [gentoo-user] Re: Finally got a SSD drive to put my OS on

[Dale <rdalek1967@gmail.com>]

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Frank Steinmetzger wrote:
> <<<SNIP>>>
>
> When formatting file systems, I usually lower the number of inodes from the 
> default value to gain storage space. The default is one inode per 16 kB of 
> FS size, which gives you 60 million inodes per TB. In practice, even one 
> million per TB would be overkill in a use case like Dale’s media storage.¹ 
> Removing 59 million inodes × 256 bytes ≈ 15 GB of net space for each TB, not 
> counting extra control metadata and ext4 redundancies.
>
> The defaults are set in /etc/mke2fs.conf. It also contains some alternative 
> values of bytes-per-inode for certain usage types. The type largefile 
> allocates one inode per 1 MB, giving you 1 million inodes per TB of space. 
> Since ext4 is much more efficient with inodes than ext3, it is even content 
> with 4 MB per inode (type largefile4), giving you 250 k inodes per TB.
>
> For root partitions, I tend to allocate 1 million inodes, maybe some more 
> for a full Gentoo-based desktop due to the portage tree’s sheer number of 
> small files. My Surface Go’s root (Arch linux, KDE and some texlive) uses 
> 500 k right now.
>
>
> ¹ Assuming one inode equals one directory or unfragmented file on ext4.
> I’m not sure what the allocation size limit for one inode is, but it is 
> *very* large. Ext3 had a rather low limit, which is why it was so slow with 
> big files. But that was one of the big improvements in ext4’s extended 
> inodes, at the cost of double inode size to house the required metadata.
>


This is interesting.  I have been buying 16TB drives recently.  After
all, with this fiber connection and me using torrents, I can fill up a
drive pretty fast, but I am slowing down as I'm no longer needing to
find more stuff to download.  Even 10GB per TB can add up.  For a 16TB
drive, that's 160GBs at least.  That's quite a few videos.  I didn't
realize it added up that fast.  Percentage wise it isn't a lot but given
the size of the drives, it does add up quick.  If I ever rearrange my
drives again and can change the file system, I may reduce the inodes at
least on the ones I only have large files on.  Still tho, given I use
LVM and all, maybe that isn't a great idea.  As I add drives with LVM, I
assume it increases the inodes as well.  If so, then reducing inodes
should be OK.  If not, I may increase drives until it has so many large
files it still runs out of inodes.  I suspect it adds inodes when I
expand the file system tho and I can adjust without worrying about it. 
I just have to set it when I first create the file system I guess.

This is my current drive setup. 


root@fireball / # pvs -O vg_name
  PV         VG     Fmt  Attr PSize    PFree
  /dev/sda7  OS     lvm2 a--  <124.46g 21.39g
  /dev/sdf1  backup lvm2 a--   698.63g     0
  /dev/sde1  crypt  lvm2 a--    14.55t     0
  /dev/sdb1  crypt  lvm2 a--    14.55t     0
  /dev/sdh1  datavg lvm2 a--    12.73t     0
  /dev/sdc1  datavg lvm2 a--    <9.10t     0
  /dev/sdi1  home   lvm2 a--    <7.28t     0
root@fireball / #


The one marked crypt is the one that is mostly large video files.  The
one marked datavg is where I store torrents.  Let's not delve to deep
into that tho.  ;-)  As you can see, crypt has two 16TB drives now and
I'm about 90% full.  I plan to expand next month if possible.  It'll be
another 16TB drive when I do.  So, that will be three 16TB drives. 
About 43TBs.  Little math, 430GB of space for inodes.  That added up
quick. 

I wonder.  Is there a way to find out the smallest size file in a
directory or sub directory, largest files, then maybe a average file
size???  I thought about du but given the number of files I have here,
it would be a really HUGE list of files.  Could take hours or more too. 
This is what KDE properties shows.

26.1 TiB (28,700,020,905,777)

55,619 files, 1,145 sub-folders

Little math. Average file size is 460MBs. So, I wonder what all could be
changed and not risk anything??? I wonder if that is accurate enough???

Interesting info.

Dale

:-) :-)


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