[OpenAFS] OpenAFS and Raid

Neulinger, Nathan nneul@umr.edu
Tue, 18 Dec 2001 10:44:02 -0600


He was referring to my comment about just mounting the parent dir RW, which
would result in the behavior he described. 

-- Nathan

------------------------------------------------------------
Nathan Neulinger                       EMail:  nneul@umr.edu
University of Missouri - Rolla         Phone: (573) 341-4841
Computing Services                       Fax: (573) 341-4216


> -----Original Message-----
> From: Hartmut Reuter [mailto:reuter@rzg.mpg.de] 
> Sent: Tuesday, December 18, 2001 10:43 AM
> To: Derek Atkins
> Cc: Neulinger, Nathan; OpenAFS Info List
> Subject: Re: [OpenAFS] OpenAFS and Raid
> 
> 
> 
> 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)
> > > > > 
> -----------------------------------------------------------------
> > > > > _______________________________________________
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> > > > > 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)
> -----------------------------------------------------------------
>