Re: How git affects kernel.org performance

On Sun, 7 Jan 2007 11:50:57 +0100 (MET) Jan Engelhardt wrote:

On Jan 7 2007 10:03, Willy Tarreau wrote:

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On Sun, Jan 07, 2007 at 12:58:38AM -0800, H. Peter Anvin wrote:

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[..]
entries in directories with millions of files on disk. I'm not
certain it would be that easy to try other filesystems on
kernel.org though :-/

Changing filesystems would mean about a week of downtime for a server. 
It's painful, but it's doable; however, if we get a traffic spike during 
that time it'll hurt like hell.

Then make sure noone releases a kernel ;-)

maybe the week of LCA ?

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However, if there is credible reasons to believe XFS will help, I'd be 
inclined to try it out.

Hmmm I'm thinking about something very dirty : would it be possible
to reduce the current FS size to get more space to create another
FS ? Supposing you create a XX GB/TB XFS after the current ext3,
you would be able to mount it in some directories with --bind and
slowly switch some parts to it. The problem with this approach is
that it will never be 100% converted, but as an experiment it might
be worth it, no ?

Much better: rsync from /oldfs to /newfs, stop all ftp uploads, rsync
again to catch any new files that have been added until the ftp
upload was closed, then do _one_ (technically two) mountpoint moves
(as opposed to Willy's idea of "some directories") in a mere second
along the lines of

  mount --move /oldfs /older; mount --move /newfs /oldfs.

let old transfers that still use files in /older complete (lsof or
fuser -m), then disconnect the old volume. In case /newfs (now
/oldfs) is a volume you borrowed from someone and need to return it,
well, I guess you need to rsync back somehow.

---
~Randy