[OpenAFS] OpenAFS and Raid
Derek Atkins
warlord@MIT.EDU
18 Dec 2001 11:52:56 -0500
Hartmut: If you mounted /afs/mpg.de/user (the volume where all user
homedirs are mounted) RW, as suggested by Nathan below, then it is NOT
(effectively) replicated.
However, as you mentioned earlier, you do mount each homedir RW
as opposed to mounting the parent (user) volume RW. This would
be the "right thing" to do.
-derek
Hartmut Reuter <reuter@rzg.mpg.de> writes:
> I do not understand why the availability of all user homedirs should
> depend on a single machine. The volume where the mountpoints for the
> user volumes are in is replicated, of course. The "backup-machine" with
> the additional RO-volumes is an add-on which increases availability or,
> at least, reduces possible down-times. Our cell is not really small (17
> TB)!
>
> Hartmut
>
> Derek Atkins schrieb:
> >
> > Yes, but I suspect that's not the behavior you would want.
> > Unless you have a relatively small cell, do you REALLy want
> > all of your user homedir availability to be dependent upon
> > a single machine?
> >
> > -derek
> >
> > "Neulinger, Nathan" <nneul@umr.edu> writes:
> >
> > > You could just mount /afs/mpg.de/user RW. That would force it.
> > >
> > > -- Nathan
> > >
> > > ------------------------------------------------------------
> > > Nathan Neulinger EMail: nneul@umr.edu
> > > University of Missouri - Rolla Phone: (573) 341-4841
> > > Computing Services Fax: (573) 341-4216
> > >
> > >
> > > > -----Original Message-----
> > > > From: Derek Atkins [mailto:warlord@MIT.EDU]
> > > > Sent: Tuesday, December 18, 2001 9:40 AM
> > > > To: Hartmut Reuter
> > > > Cc: Petros Triantafyllidis; OpenAFS Info List
> > > > Subject: Re: [OpenAFS] OpenAFS and Raid
> > > >
> > > >
> > > > Hartmut,
> > > >
> > > > How do you prevent the /afs/mpg.de/user/foo from accessing the
> > > > readonly mountpoint? Do you specifically mount all user.foo
> > > > volumes -rw?
> > > >
> > > > -derek
> > > >
> > > > Hartmut Reuter <reuter@rzg.mpg.de> writes:
> > > >
> > > > > 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
> > > > > >
> > > > > > _______________________________________________
> > > > > > OpenAFS-info mailing list
> > > > > > OpenAFS-info@openafs.org
> > > > > > https://lists.openafs.org/mailman/listinfo/openafs-info
> > > > >
> > > > > --
> > > > > -----------------------------------------------------------------
> > > > > 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)
> > > > > -----------------------------------------------------------------
> > > > > _______________________________________________
> > > > > OpenAFS-info mailing list
> > > > > OpenAFS-info@openafs.org
> > > > > https://lists.openafs.org/mailman/listinfo/openafs-info
> > > >
> > > > --
> > > > Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
> > > > Member, MIT Student Information Processing Board (SIPB)
> > > > URL: http://web.mit.edu/warlord/ PP-ASEL-IA N1NWH
> > > > warlord@MIT.EDU PGP key available
> > > > _______________________________________________
> > > > OpenAFS-info mailing list
> > > > OpenAFS-info@openafs.org
> > > > https://lists.openafs.org/mailman/listinfo/openafs-info
> > > >
> > > _______________________________________________
> > > OpenAFS-info mailing list
> > > OpenAFS-info@openafs.org
> > > https://lists.openafs.org/mailman/listinfo/openafs-info
> >
> > --
> > Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
> > Member, MIT Student Information Processing Board (SIPB)
> > URL: http://web.mit.edu/warlord/ PP-ASEL-IA N1NWH
> > warlord@MIT.EDU PGP key available
> > _______________________________________________
> > OpenAFS-info mailing list
> > OpenAFS-info@openafs.org
> > https://lists.openafs.org/mailman/listinfo/openafs-info
>
> --
> -----------------------------------------------------------------
> 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)
> -----------------------------------------------------------------
--
Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
Member, MIT Student Information Processing Board (SIPB)
URL: http://web.mit.edu/warlord/ PP-ASEL-IA N1NWH
warlord@MIT.EDU PGP key available