gvinum performance issues

[Marco Haddad]

Hello,

I've seen somewhere a thread about this topic, but I can't find it here,
where I think it ought to be.
So, let me describe what is going on: I had this Core2 Quad running as
Internet gateway, web server and file server, doing fine with FreeBSD 7.2
for a long time. The problem came with the upgrade to version 8.0.

It is composed of two gmirror volumes, each build up from a pair of 500GB
disks. They are not the problem. Because of the nature of this server role,
a long history of backups is necessary, and for that task there was a single
1.5TB disk, which got filled up after some time.

Then I decided to get two more 1.5TB disks and use gvinum to build a raid5
volume for the backup. That was done with success. The backup operation that
used to take four hours to complete, now was taking 6 hours, what was ok for
an over night backup.

Then I decided to upgrade to version 8.0, so I could grow the volume just
adding more disks, without losing its content. The upgrade went well with no
problems at all, but the backup was already running for three days when I
realized that something was wrong. The transfer rate was around 200KB/s, a
fraction of what it was with version 7.2.

After trying all possible solutions found, including rebuilding parity,
destroying the volume and recreating under version 8.0, I decided the just
concat the three disks and let the backup roll, while I seek for help.

I read somewhere Ulf telling that he had received a number of similar
complaints, but there was no solution on that thread yet.

So if someone here had this problem solved, please enlighten me.

Thanks in advance,
Marco Haddad