We use TSM which can be very write intensive. Our SATA disk is coming
from a Clarrion here's how the Clarrion Disk is setup is may help...
With this Disk Config we get 168GB per hour per stream to a 3592Tape
Drive
Clariion: CX700
Drives: 320 GB SATA
Raid Sets: Raid 3 (4+1) ((5 drives per set))
Number of Luns per Raid Set: 2
Approx Lun Size: 594GB
Stripe Size: 128K
-----Original Message-----
From: veritas-bu-admin AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu] On Behalf Of Tim Berger
Sent: Monday, August 15, 2005 1:02 PM
To: Eric Ljungblad
Cc: Dean; Matt Clausen; veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] Fast backup to tape but slow backup to disk on
NBU 5.1MP3
For a 6 drive 10 raid, I got about 140MB/sec reads & 95MB/sec writes.
It's a shame that it takes so many disks to get good write performance
on a redundant raid.
These are all 400GB SATA disks.
On 8/14/05, Eric Ljungblad <Eric.Ljungblad AT copleypress DOT com> wrote:
>
>
>
> Good testing,
>
>
>
> Have you tried RAID 10 / (1/0) or tried (0+1) ?
>
>
>
> ________________________________
>
>
> From: veritas-bu-admin AT mailman.eng.auburn DOT edu
> [mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu] On Behalf Of Dean
> Sent: Sunday, August 14, 2005 5:15 AM
> To: Tim Berger
> Cc: Matt Clausen; veritas-bu AT mailman.eng.auburn DOT edu
> Subject: Re: [Veritas-bu] Fast backup to tape but slow backup to disk
> on NBU 5.1MP3
>
>
>
>
> "Matt, writing multiple concurrent streams to the same set of disks
> may be hurting performance. One at a time may yield better results."
>
> I believe Tim's got it right. SATA is best at serial writes. If you
> feed it two or more streams, that is effectively random writes, and
> performance suffers badly.
>
>
>
>
> On 8/12/05, Tim Berger <tim.berger AT gmail DOT com> wrote:
>
> Matt, writing multiple concurrent streams to the same set of disks may
> be hurting performance. One at a time may yield better results.
>
> I'm in the process of building out some staging servers myself for
> nbu
> 5.1 - been doing a bunch of bonnie++ benchmarks with various configs
> for Linux using a sata 3ware controller.
>
> On fedora core 3 (I know it's not supported):
>
> Raid5, 5 disks I got ~30MB/sec writes & 187MB/sec reads. Raid 50
> with striping over 3 4-disk raid5's got 49MB/sec writes, 120 MB/sec
reads.
> For raid0, w/10 disks, got a nice 158 MB/sec writes, and 190MB/sec
> reads.
>
> I'm partial to raid5 for high availability even with poor write
> performance.. I need to stream to lto3, which tops out at 180 MB/sec.
> If I went with raid0 and lost a disk, then a media server would take
> a dive, backups would fail, and I'd have to figure out what data
> failed to make it off to tape. I'm not sure how I'd reconcile a lost
> dssu with netbackup. If I wanted to to use the dssu's for doing
> synthetic fulls, then that further complicates things if a staging
unit is lost.
>
> Any thoughts on what the netbackup fallout might be on a dssu loss?
>
> Even though it's not supported yet, I was thinking of trying out
> redhat enterprise linux 4, but I'm seeing really horrible disk
> performance (eg. 100MB/sec reads for raid5 vs the 187MB/sec on fc3).
>
> Maybe I should try out the supported rhel3 distribution. ;-) I
> don't have high hopes of that improving performance at the moment.
>
> On 8/10/05, Ed Wilts <ewilts AT ewilts DOT org > wrote:
> > On Wed, Aug 10, 2005 at 12:43:39PM -0400, Matt Clausen wrote:
> > > Yet when I do a backup to disk, I see decent performance > > on
> one stream (about 8,000KB/s or so) but the other streams will drop to
> > > around 300-500KB/s.
> > >
> > > NUMBER_DATA_BUFFERS = 16
> > > NUMBER_DATA_BUFFERS_DISK = 16
> > >
> > > SIZE_DATA_BUFFERS = 262144
> > > SIZE_DATA_BUFFERS_DISK = 1048576 > > > > and I see this
> performance on both the master server disk pool AND a > > media
> server disk pool. The master server is a VxVM concat volume set of >
> > 3x73GB 10,000RPM disks and the media server is an external raid 5
> volume > > of 16x250GB SATA disks.
> >
> > I don't believe you're going to get good performance on a 16 member
> > RAID5 set of SATA disk. You should get better with a pair of 8
> member > raid sets, but SATA is not fast disk and large raid 5 sets
> kill you on > write performance. If you're stuck with the SATA
> drives, configure them > as 3 4+1 RAID5 sets and use the 16th member
> as a hot spare. You'll have > 3TB of disk staging instead of about
> 3.8TB but it will perform a lot > better.
> >
> > --
> > Ed Wilts, Mounds View, MN, USA
> > mailto:ewilts AT ewilts DOT org
> > _______________________________________________
> > Veritas-bu maillist -
> Veritas-bu AT mailman.eng.auburn DOT edu
> >
> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
> >
>
>
> --
> -Tim
>
> _______________________________________________
> Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
>
>
--
-Tim
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