Xen and the art of Database performance
McDougall, Marshall (FSH)
Marshall.McDougall at gov.mb.ca
Thu Oct 25 13:42:41 UTC 2007
>From: redhat-list-bounces at redhat.com
>[mailto:redhat-list-bounces at redhat.com] On Behalf Of J.
>Sent: Wednesday, October 24, 2007 2:59 PM
>To: General Red Hat Linux discussion list
>Subject: Re: Xen and the art of Database performance
>--- "McDougall, Marshall (FSH)"
><Marshall.McDougall at gov.mb.ca> wrote:
>> A while back we took delivery of several Dell 2950
>> servers to update our
>> hardware environment which supports our Ingres,
>> Sybase and DB2 systems.
>> Ingres 2.6 and DB2 were running on RHEL 2.1, Sybase
>> was running on
>> RHEL3. We were hoping to be able to maintain the
>> same levels software,
>> but the new hardware is not supported by RHEL2.1.
>> This is where the fun
>> starts. I built up several RHEL4 servers and
>> installed the Database
>> systems on them and gave them to the DBA's to test.
>> They promptly came
>> back and said that they were up to 7 times slower
>> than the previous
>> hardware platforms, with the exception of DB2. I
>> ran some OS benchmarks
>> and they came back up to 7 times faster than the
>> previous hardware. We
>> worked on various tweaks and tunes to the OS and
>> DBMS to no avail.
>> At that point we started to engage the
>> vendors/support orgs for the
>> various products. Sybase could do nothing to
>> improve performance on the
>> RHEL4 server, so we tried RHEL5(or advanced platform
>> or whatever they
>> are calling it this week). The performance was just
>> as dismal. We ended
>> up going back to RHEL3U9 to get the Sybase
>> environment to an acceptable
>> performance level.
>> Ingres is another story. First they said try Ingres
>> 2006. It worked,
>> but it has significant implications to our OpenRoad
>> environment, and as such is not really an option. I
>> went the same route
>> as before with the various flavours of RHEL and it
>> made no difference.
>> Finally, I built a RHEL5 server, installed VMWare
>> Server, and created a
>> RHEL2.1 guest on that. We now have performance
>> where we want it. The
>> downside is that on my server with 8GB of ram I can
>> only use 3.6GB for
>> the VM.
>> My options as I see them now are; Install VMWare ESX
>> and see if that
>> buys me anything, or spend the time and effort to
>> see if Xen will be of
>> benefit. The problem with the latter is that
>> according to the doc RHEL
>> 2.1 is not a supported OS on RH5.
>Indeed, XenSource does not include the appropriate
>modified kernel for RHEL 2.1 and, accordingly, is not
>officially supported on XenEnterprise 3.2 or higher.
>Notwithstanding, you can create an proper Linux kernel
>for your RHEL 2.1 by installing the same into a
>machine that has the CPU virtualization extensions
>(i.e., hardware assisted virtualization).
>Once you successfully install/modify your RHEL 2.1
>under XenEnterprise in the above hardware assisted
>virtualization environment, you can use the image on
>older non-hardware assisted virtualization CPUs.
>Before going to ESX, you may want to evaluate
>XenEnterprise in price and performance. Back in
>version 3.2 of XenSource XenEnterprise, you could
>allocate to an virtual machine up to 15GB of memory.
>Disclaimer: Metztli Information Technology is an
>Xensource Certified Partner.
>> So, after all this, the gist of my post is; Has
>> anybody successfully
>> sparked up a RHEL 2.1 guest, using more than 4 GB of
>> RAM, on a RH5
>> virtual platform, or, has anyone installed Ingres
>> 2.6 on a Linux 2.6
>> kernel and made it perform at an expected level?
>> Thanks for reading
>> this far.
>> Regards, Marshall
>> redhat-list mailing list
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>Jose R Rodriguez
Thanks for the input Jose. It sounds like it's doable with Xen, but it
also sounds like it's painful. Yesterday I downloaded a time bomb trial
of ESX and had it and a RHEL2.1 VM running in about 1.5 hours. I've
taken a lot longer than that just trying to understand the Xen docs that
I can find.
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