[Tfug] Filesystem suggestion

[John Gruenenfelder]

On Tue, Jun 15, 2010 at 11:17:37PM -0700, erich wrote:
>     I have a jfs system under LVM. That is the partition is
>expandable  over
>one or more hard drives.
>
>      Why jfs? Well, because I want proficiency at handling large
>files. Copying,
>deleting, or moving, (which amounts to doing both), can be time consuming
>for large file sizes (>= 5G)
>
>      Why LVM?  Because it is possible to add other drives as your library
>expands. There is a caveat here: If the partition is resized, a
>reformat operation
>is inevitable. Provision must be made to copy off the contents of the old
>partition, and restore these contents  on the new.
>
>       My system  has had several, (inadvertent), crashes, and jfs
>came thru
>with flying colors. I was still nervous about the userland since that
>is still
>an ext3 filesystem.
>
>Erich

Hi Erich,

I suppose I should have mentioned in my first post that I'm already making
heavy use of LVM.  Right now my desktop and netbook are root-on-LVM-on-cryptfs
and my fileserver is root-on-LVM-on-RAID5-on-cryptfs.  Both of these setups
necessitate, as another post just mentioned, that /boot have its own partition
because it can't read all of that at boot time.  Root needs to be unlocked and
have all the metadata read and whatnot.

One nice feature I've always liked about XFS, which mostly removes the
partition resize problem you mention, is that you can grow the filesystem
*while* it is live and mounted.

This is very handy with LVM.  With disks so huge these days, I always leave at
least 10-20GB unallocated in my LVM pool.  Then, later, if I find that I've
made root, var, or whatever too small, I can grow its logical volume the
amount I want and then grow the XFS filesystem on that volume (by default, it
will grow to use all the space in its partition/volume).  In practice, if
anything must change, it's almost always /usr that I've made too small since
it holds so much data and programs are always growing and/or I'm always
installing more than before.

Also, XFS handles large files extremely well and quickly.  This is one of the
primary reasons I use it on my file server; it doubles as my MythBox and has
no shortage of very large files.

That said, I think I'll have to read up a bit on JFS because my desktop
machine, unlike the file server, does not contain mostly large files.  It's
the opposite.  Supposedly this is what reiserfs was good at, but last I heard
it's sort of in development limbo, for obvious reasons.  Maybe that's changed
now?  Does it have new leadership?


-- 
--John Gruenenfelder    Systems Manager, MKS Imaging Technology, LLC.
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