Subject: Re: OT: recommendation for vm tuning for anoncvs mirror?
To: Jeff Rizzo <riz@tastylime.net>
From: Thor Lancelot Simon <tls@rek.tjls.com>
List: netbsd-users
Date: 02/26/2005 19:47:36
On Sat, Feb 26, 2005 at 04:04:09PM -0800, Jeff Rizzo wrote:
> 
> Is the purpose of this for LockDir?  Not knowing a tremendous amount 
> about CVS's internals myself, I wonder if some of the read-only 
> repository patches available in later (than the 1.11.17 that comes 
> w/NetBSD) CVS might help with this?  I wasn't originally planning on 
> having separate spindles, but clearly I need to rethink this... I 
> suppose I can simply not raid the disks, as all the data is mirrored 
> from other sources anyway - I'll live with a dead disk taking the system 
> offline.

Read-only repositories don't use locks.  I don't know what changes
you're referring to that aren't in the CVS in the NetBSD tree: I can
assure you that anoncvs.netbsd.org has not run with locks, ever.

CVS uses /tmp for generating old (or branch) revisions of files, for
generating diffs, etc.  It creates mirror directory structures of as
much of the repository as it's been asked to check out, in /tmp, for
every checkout (or diff, etc.).  This means creating tens of thousands
of directories and files per copy, which is the reason for all of the
effort to optimize the system to run efficiently with huge numbers of
small directories.

I suggest that you mirror / (and /usr, and /var, etc. if those are
separate filesystems) and then use one partition on each of the two
mirror disks for /anon-root and /anon-root/tmp respectively.  If you
lose either disk, you can just drop a new disk in and trivially
recreate either the anon-root you lost or let the boot process
recreate an empty /anon-root/tmp for you. :-)

Thor