[OpenAFS] OpenAFS and Raid

[Hartmut Reuter]

Petros Triantafyllidis schrieb:
> 
> Hi all,
>   We are planning to install OpenAFS 1.2.2a on a new server running RH
> 7.1, kernel 2.4.16smp. After the testing period this machine will be
> the second server of a primary one which runs Solaris 2.6 and Transarc
> AFS 3.6.
> 
> The thought is to implement software RAID on the Linux box. The question
> is whether raid-5 can co-live with AFS. What are the possible pitfalls and
> how should it be done in order we obtain the maximum of performance
> (assuming redundancy is a must)?

We are running a machine with SuSE 7.3 (kernel 2.4.10) with 2 RAID5s,
LVM and a huge reiserfs with 900 GB on top of this. Reading and writing
performance seems to be ok (both ~ 36 MB/s). The only problem I have is
that the RAID seems not to detect a bad disk by itself. When a disk dies
we get a lot of SCSI-timeout messages in /var/log/messages, but it
doesn't understand that the disk is dead. Worse: we have to reboot after
a "raidsetfaulty" for the disk in order to get him to rebuild the RAID.
We use this partition for readonly-volumes of the user's
home-directories. I have written a "vos convert" command (MR-AFS) to
convert a RO-volume to a RW-volume. This allows to come up after the
loss of a partitioon much faster than if you had to restore the volumes
from tape. So we do each night a "vos release" instead of a "vos
backupsys".

Hartmut


> 
> Thanks a lot in advance,
> Petros
> 
> --
> Dr. TRIANTAFYLLIDIS PETROS         E-MAIL: trian@itc.auth.gr
> ^^^^^^^^^^^^^^^^^^^^^^^^^^         http://afs.itc.auth.gr/~trian
> AFS Technical Support Team
> Aristotle University - Information Technology Center (KYTP)
> POBox 888,54006 Thessaloniki-GREECE-TEL:+30-31-998444,FAX:998302
> 
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-- 
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Hartmut Reuter                           e-mail reuter@rzg.mpg.de
					   phone +49-89-3299-1328
RZG (Rechenzentrum Garching)               fax   +49-89-3299-1301 
Computing Center of the Max-Planck-Gesellschaft (MPG) and the
Institut fuer Plasmaphysik (IPP)
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