Re: XFS filessystem for Datawarehousing

Milen,

For the past year, I have been running odbc-bench on a dual-opteron with
4GB of RAM using a 8GB sample data. I found the performance difference
between EXT3, JFS, and XFS is +/- 5-8%. This could be written-off as
"noise" just for normal server performance flux. If you plan on using the
default kernel, ext3 will likely perform best (what I found). When I added
my own kernel, ext3 performed fair. What I've had to consider is what does
each file system offer me as far as data integrity goes.

You'll find greater ROI on performance by investing your time in other areas
than chasing down a few percentage point (like I have done). If you could
borrow more RAM and/or more discs for your tests, Testing newer kernels and
read-ahead patches may benefit you as well.

Best of luck.

Steve Poe

On 8/2/06, Milen Kulev <makulev(at)gmx(dot)net> wrote:
>
> Hi Like, Mark , Alvaro and Andrew,
>
> Thank you very much for sharing you experience with me.
> I want to compare DHW performance of PG/Bizgres on different filesystems
> and difffrent
> Block sizes.
>
> The hardware will be free for me in a week or too (at a moment another
> project is running on it) and then I will test
> diffrenet setups and will post the results.
>
> I MUST (sorry, no other choice) use SLES6 R3, 64 bit. I am not sure at all
> that I will get enough budget to get
> approapriate RAID controller, and that is why I intent to use software
> RAID.
>
> I am pretty exited whether XFS will clearly outpertform ETX3 (no default
> setups for both are planned !). I am not sure
> whether is it worth to include JFS in comparison too ...
>
>
> Best Regards,
> Milen Kulev
>
> -----Original Message-----
> From: Luke Lonergan [mailto:llonergan(at)greenplum(dot)com]
> Sent: Wednesday, August 02, 2006 4:43 AM
> To: Milen Kulev; pgsql-performance(at)postgresql(dot)org
> Subject: Re: [PERFORM] XFS filessystem for Datawarehousing
>
>
> Milen,
>
> On 8/1/06 2:49 PM, "Milen Kulev" <makulev(at)gmx(dot)net> wrote:
>
> > Is anyone using XFS for storing/retrieving relatively large amount of
> > data (~ 200GB)?
>
> I concur with the previous poster's experiences with one additional
> observation:
>
> We have had instabilities with XFS with software RAID (md) on 32-bit Xeons
> running RedHat4 U3 with the Centos 4.3
> unsupported SMP kernel. XFS would occasionally kernel panic under load.
>
> We have had no problems with XFS running on the same OS/kernel on 64-bit
> under heavy workloads for weeks of continuous
> usage. Each server (of 16
> total) had four XFS filesystems, each with 250GB of table data (no
> indexes) on them, total of 16 Terabytes. We tested
> with the TPC-H schema and queries.
>
> We use the default settings for XFS.
>
> Also - be aware that LVM has a serious performance bottleneck at about
> 600MB/s - if you are working below that
> threshold, you may not notice the issue, maybe some increase in CPU
> consumption as you approach it.
>
> - Luke
>
>
>
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