[Linux-cluster] Setting up a GFS cluster

[hai wu]

Hi Celso,
I have one PV220S for test right now. Where can I set up the data transfer
rate to 160 MB/s instead of 320 MB/s?
Thanks,
Hai


On 8/15/06, Celso K. Webber <celso at webbertek.com.br> wrote:
>
> Hello Brendan,
>
> Although Dell hardware is an excellent choice for Linux, the PV220S
> solution is terrible at performance under a cluster environment.
>
> The reason is that the PV220S itself does not manage RAID devices, it is
> in fact a JBOD (Just a Bunch Of Disks). The RAID management is done by
> the SCSI controllers within the servers (PERC 3/DC or PERC 4/DC).
>
> Since there is a possibility of one of the machines going down, together
> with data in the controller's write cache, this solution automatically
> disable the write cache (write through mode) when you set the
> controllers in "cluster mode".
>
> The end result is very poor performance, specially on write operations.
> It's not uncommon that Dell provides the PV-220S with 15K RPM disks to
> compensate this performance penalty due to lack of write cache.
>
> As far as I can tell, Red Hat did support the PV220S solution in the
> past, during the RHEL 2.1 era, but it is not supported anymore as
> certified shared storage for cluster solutions (RHCS or RHGFS).
>
> If you still plan to go on, be warned that the PV220S performs better in
> Cluster Mode if you set up the data transfer rate to 160 MB/s instead of
> 320 MB/s (the PERC 3/DC supports transfer rates of up to 160 MB/s while
> the PERC 4/DC supports up to 320 MB/s). This is a known issue at Dell
> support queues.
>
> As an extra information, there were too many problems about reliability
> with the PV220S when used in Cluster Mode, this can be seen by the large
> amount of firmware updates for the PERC 3/DC and 4/DC (LSI Logic based
> chipset, megaraid driver on Linux). More recent firmware versions seem
> to have corrected most logical drive corruption problems I've
> experienced, so I believe the PV220S is still worth a try if you can
> live with the poor performance issue.
>
> Maybe a Dell|EMC AX-100 using iSCSI could a better choice with a not so
> high price tag.
>
> Sorry for the long message, I believe this information can be useful to
> others.
>
> Best regards,
>
> Celso.
>
> Brendan Heading escreveu:
> > Hi all,
> >
> > I'm planning to build a cluster using a pair of PE1950s, using RHEL 3
> > (or 4) with RHCS. Plan at the moment is to use GFS. Most of our stuff is
> > Dell, therefore the obvious choice is to use a Dell PowerVault 220S as
> > the shared storage device.
> >
> > Before I kick off with this idea I'd be interested to hear if anyone had
> > any issues with this kind of setup, or if there were any general
> > performance problems. Are there other SCSI enclosures which might be
> > better or more appropriate for these purposes ?
> >
> > Regards
> >
> > Brendan
> >
> > --
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> > Linux-cluster at redhat.com
> > https://www.redhat.com/mailman/listinfo/linux-cluster
> >
>
> --
> *Celso Kopp Webber*
>
> celso at webbertek.com.br <mailto:celso at webbertek.com.br>
>
> *Webbertek - Opensource Knowledge*
> (41) 8813-1919
> (41) 3284-3035
>
> --
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>
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