Justin,
"My concerns are that we will slow down the client backups when we have so
many clients running in a small backup window.
If we use SATA or FC ATA drive for the primary disk storage pool."
We use ATA in an EMC Clariion as primary disk storage pools. We keep TSM
caching turned OFF, simply because the disks are so large that caching
doesn't buy us much.
We have found that using EMC five-disk RAID-3 arrays for disk pools yields
a consistent 40-50 MB/s when pushed by our 2-way 6H1. We use EMC
PowerPath to load-balance the data paths to the LUNs.
On the other hand, because the ATA hot spare is in the TSM pod, we also
created a four-disk RAID-5 array. On that array, we're lucky if we peak
at 18 MB/s and sustained performance is usually 12 MB/s or less. All
measurements obtained via topas. EMC Clariion code is optimized for (4 x
n + 1) disk arrays. I don't know about IBM's. So that's a factor in the
performance difference between the two types of arrays.
Our two RAID-3 arrays are 1188 GB each, and our one RAID-5 array is 891
GB.
We target our file servers to the RAID-3 arrays and have not observed any
performance issues. Our Domino and Oracle databases write straight to
LTO-1 tape. We point small application servers and CAD workstations at
the RAID-5 array, and for those clients, performance is not really an
concern. If a backup takes a few minutes longer, so what?
We have about 160 clients backing up between 8 pm and 6 am. We have no
issues about meeting backup windows since all backups are "hot". Our
largest file server has almost two million files, and a typical backup
takes about five hours. Most of that is client directory scanning and we
are considering using journaling when we go to TSM 5.3 in a couple months.
Also, that server is now hosted by VMWare so all I/O has to pass through
the VMWare kernel. We have seen a performance drop using VMWare,
especially when sending to ATA disks.
On last night's backup of that file server, the average network data
transfer rate was just under 10 MB/s. We can live with that. I've
personally seen the 6H1 swallow 70 MB/s through its NIC so I know the TSM
server is not a bottleneck.
Just info.
Tab Trepagnier
TSM Administrator
Laitram, L.L.C.
"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote on 07/12/2005
03:54:18 PM:
> OK May be I was not clear what we would use the SATA or FC ATA for
would
> be the primary disk storage pools for nightly backup window
> then next morning we would be migrating the backup data to tapes ( FC
3592
> jaguar drives ), current primary storage pools are Enterprise class
> (shark disks) and our disk storage pool is currently 1.7 TB for nightly
> backup that is what we call cache pool, on one TSM Server and another
> TSM server we have 1.6 TB of primary storage pool, then we have a small
TSM
> server that has 1/2 TB of primary storage pool. In all we backup up 513
> clients nightly with the 3 TSM servers and data that is backed up runs
> between 2.7 TB to 3.2 TB. in a backup window of 6 to 8 hours. We do
have
> about 100
> Oracle RMAN backups included in the backup window running TSM TDPO
backups.
> If you need more information please let me know.
>
> My concerns are that we will slow down the client backups when we have
so
> many clients running in a small backup window.
> If we use SATA or FC ATA drive for the primary disk storage pool.
> Thanks
>
> Justin Case
>
>
>
>
>
>
>
>
>
> Jin Bae Chi
> <Jbaechi AT CSCC DOT EDU
> > To
> Sent by: "ADSM: ADSM-L AT VM.MARIST DOT EDU
> Dist Stor cc
> Manager"
> <[email protected] Subject
> .EDU> Re: How are TSM admins using SATA
> for cache pools?
>
> 07/12/2005 08:24
> AM
>
>
> Please respond to
> "ADSM: Dist Stor
> Manager"
> <[email protected]
> .EDU>
>
>
>
>
>
>
> Justin,
>
> You may need to tell us more about your configuration and how much data
and
> how long you need to keep the data before any migration with cache
turned
> on/off. As you mentioned, you may not need the enterprise class stg for
> these particular diskpools unless your SLA requires certain strictness
in
> performance. Because of the nature of SATA, write I/Os will be
troublesome
> in any case, so make sure that the controller have enough cache and
destage
> it later. Some people make mistake buying with single controller config,
> but remember that you can't afford to lose it during client backups.
Look
> for the new SATA II which comes with a lot of fixes and also,
>
> TSM takes pretty much any disks that OS sees as available so consider
> giving multiple diskpools. Depending on what tape storage you have, but
> writing direct to tape device today is not a bad idea in many cases, so
> consider not only diskpool for immediate writes, but also tape devices
such
> as FC LTO2 or LTO3. For the better pricing, ATA drives with proper RAID
> config could be considered.
>
> When configured correctly, SATA drives will be performing as good as
other
> types of disks. I've been running and happy with them for a while for
TSM
> and other applications. Hope this helps.
>
>
> Gus
>
>
> >>> justin.case AT DUKE DOT EDU 07/11/05 10:01 PM >>>
>
> How are TSM admins using SATA disks for cache pools ?
>
> What type of SATA disks are being used and at what raid levels ?
>
> How satisfied are you with the backup times with SATA disks for cache
pools
> on TSM ?
>
> We are looking at SATA for TSM cache pools is why the questions because
> we are using enterprise class storage for cache pools on TSM currently
at a
> high cost.
>
> Looking for cheaper disks for TSM cache pools.
> Thanks
>
> Justin Case
> TSM Administrator/Storage Administrator
> IT Analyst OIT Infrastructure Support
> 334 Blackwell Street
> 2nd floor Suite 2108 Durham,NC 27701
> Duke University
> Email: justin.case AT duke DOT edu
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