Do not recommend non-raid ESS disks for TSM that you will mirror. The ESS
defines very large disk groups at a time as RAID-5 or RAID-0 and with the
ESS-800 you can use RAID-1 (actually I think it is RAID-10).
The log is a sequential write only workload for all intensive purposes. In
the case of the ESS that is a wonderful case to use RAID-5.
In the case of the database, we have defined our LUNs at about 1/4 the
database size each, our case 32GB each (1 each per disk group in the ESS).
That spreads the IO as widely as possible. We stripe this into a JFS file
system.
Then in AIX we set the max page read ahead to 256 and let it fly. Database
backups run at about 85GB/hr.
The ESS likes its IO spread evenly across the disk groups for the best
performance.
There are other schools of thought and recommendations on this subject. The
recommendations are always hardware dependent. So, find a matching hardware
configuration with some folks and discuss their experiences.
Paul D. Seay, Jr.
Technical Specialist
Naptheon Inc.
757-688-8180
-----Original Message-----
From: Raghu S [mailto:raghu AT COSMOS.DCMDS.CO DOT IN]
Sent: Saturday, October 26, 2002 1:16 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: RAID5 in TSM
Hi ,
I thank all for your suggestions.I removed the mirrors of db and log.There
is a great improvement in the performance.I am recommending the customer to
have non RAID disks for db and log.Then i mirror the db and log.
Regards
Raghu.
"Seay, Paul"
<seay_pd@NAPT To: ADSM-L AT VM.MARIST DOT EDU
HEON.COM> cc:
Sent by: Subject: Re: RAID5 in TSM
"ADSM: Dist
Stor Manager"
<ADSM-L AT VM DOT MA
RIST.EDU>
10/24/2002
10:00 AM
Please
respond to
"ADSM: Dist
Stor Manager"
The actual published F20 throughput numbers are 380 MB/sec read, 45K IO/sec,
160 MB/sec write from an applications point of view. Though these were old
ones and some microcode improvement have improved these numbers especially
for small block sizes. Remember, these are subject to discussion as well
because they depend on the block size of the data. I believe these are
based on 4K block sizes.
And as you say, there are not many application servers that can absorb data
at these rates.
Paul D. Seay, Jr.
Technical Specialist
Naptheon Inc.
757-688-8180
-----Original Message-----
From: Gianluca Mariani1 [mailto:gianluca_mariani AT IT.IBM DOT COM]
Sent: Thursday, October 24, 2002 9:26 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: RAID5 in TSM
I would just like to add something. the manuals are sometimes misleading.
ESS runs at a "theoretical" speed of 1280 MB/s yes. that's because you count
the fiber channel connections towards the outside. but the internal busses
are 4 133MB/s PCI busses. that makes a max throughput from the cache to the
arrays of 512MB/s (I'm not talking about the new 800 which I'm not familiar
with). and those are split between the two halves of an ESS; so a lot of
care has to be taken in how you configure volumes and spread them through
the machine. this little "trick" is what every vendor does, us (IBM),
Hitachi, EMC etc. in the same fashion you will not get the "claimed"
throughput of an Hitachi or EMC machine in 99% of real world cases. the ESS
arrays are REALLY RAID5 arrays, and the performance lag with respect to a
RAID 1 machine is negligible in the vast majority of cases. there will be
those few "top notch" customers who will not be satisfied with this, and, if
they have the money (because RAID 5 is basically a trade off between
performance and cost), they will go for a RAID 1 machine. I feel that saying
things honestly would save us all lots of trouble and confusion and money.
this pun is obviously directed to the Sales departments of all our
companies...
Cordiali saluti
Gianluca Mariani
Tivoli TSM Global Response Team, Roma
Via Sciangai 53, Roma
phones : +39(0)659664598
+393351270554 (mobile) gianluca_mariani AT it.ibm DOT com
----------------------------------------------------------------------------
------------------------
"The people of Krikkit,are, well, you know, they're just a bunch of real
sweet guys, you know, who just happen to want to kill everybody. Hell, I
feel the same way some mornings..."
"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote on 24/10/2002
14.54.40:
> Raghu,
>
> as you wrote it was already discussed on this list. In last thread we
with
> Paul confirmed both that ESS is a different beast. Very, very deep
> under the covers of ESS there are really RAID-5 arrays. But the
> addtional
layers
> on top of them is making ESS better than nearly all RAID-1
> implementations. Data taken from ESS manuals - ESS is capable to feed
> the data at ....
1280
> MB/s (yes, one 1,28 gigabytes per second) !!! And with new 800 model
> it
is
> even better.
> So answer again is "it depends". Not all RAID-5 are created equal. If
> you can afford ESS this is (IMO) the best answer for TSM.
>
> Zlatko Krastev
> IT Consultant
>
>
>
>
>
>
> Raghu S <raghu AT COSMOS.DCMDS.CO DOT IN>
> Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> 23.10.2002
> 07:30 Please respond to "ADSM: Dist Stor Manager"
>
>
> To: ADSM-L AT VM.MARIST DOT EDU
> cc:
> Subject: Re: RAID5 in TSM
>
>
> Paul,
>
>
> keeping TSM database,log and disk storage pool on RAID5 degrades the
> performance???
>
> Regards
>
> Raghu
>
>
>
> "Seay, Paul"
> <seay_pd@NAPT To: ADSM-L AT VM.MARIST DOT EDU
> HEON.COM> cc:
> Sent by: Subject: Re: RAID5 in TSM
> "ADSM: Dist
> Stor Manager"
> <ADSM-L AT VM DOT MA
> RIST.EDU>
>
>
> 10/22/2002
> 06:29 AM
> Please
> respond to
> "ADSM: Dist
> Stor Manager"
>
>
>
>
>
> Are you running compression?
>
> Paul D. Seay, Jr.
> Technical Specialist
> Naptheon Inc.
> 757-688-8180
>
>
> -----Original Message-----
> From: Raghu S [mailto:raghu AT COSMOS.DCMDS.CO DOT IN]
> Sent: Tuesday, October 22, 2002 8:03 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: RAID5 in TSM
>
>
> Hi,
>
> There was a lot of discussion on this topic before.But i am requesting
TSM
> gurus give their comments again.
>
> The set up is like this.
>
> TSM Server : Windows NT 4.0 SP6, TSM 5.1.0.0
>
> 392 MB memory, P III
>
> Adaptech Ultra SCSI
>
> Hard Disk : Internal Hardware RAID 5:
>
> array A : 8.678GB * 3 : 17.356GB data and
> 8.678 GB parity
>
> array B : 35.003 GB * 3 : 70.006GB data and
> 35.003 GB parity.
>
>
> Both array A and array B are connected to the same channel.
>
> OS and TSM 5.1 are installed on array A
>
> TSM data base, recovery log and Disk storage pool are installed in
> array B.
>
> Database : 2GB+2GB = 4 GB and mirrored at TSM level on the same array
>
> Recovery Log : 500MB + 500 MB = 1 GB and mirrored at TSM level on the
same
> array
>
> Disk Storage pool : 10GB+10GB+10GB+10GB+5GB=45GB on array B
>
>
> TSM client: 4.1.2.12 ( Tivoli says 4.1.2.12 is not supported with 5.1
> Server. But i could take the backup,archive and restore with this
> combination )
>
> Number of Clients : 55, all are windows
>
> Incremental backup : 1GB/ client/day.
>
> backup window : 9AM to 6PM with 50% randamization ( all are in polling
> mode
> )
>
> LAN : 100Mbps
>
> End of the day only 10 clients could finish the backup.Remaining all
> are missing or "?" ( in progress ) or failed.
>
> Through the entire backup window the CPU load is 100% with dsmsvc.exe
> holding 98%
>
> I tested with various options. I stopped the schedular and fired 3
clients
> backup manually at the same time.Each client has 1 GB of incremental
data.
> It took three hours to finish the backup. While backing up i observed
> there was lot of idletime outs of sessions.
>
> Network choke is not there. I checked this with FTP.
>
> Whats the bottleneck here? Is RAID 5 is creating problems ( DB,log and
> storage pool all are on the RAID 5 )? I asked the customer to arrange
> a testing machine without any RAID. I will be getting that in two
> days.Before going on to the testing i like to know your comments on
> this.
>
>
>
> Regards
>
> Raghu S Nivas
> Consultant - TSM
> DCM Data Systems Ltd
> New Delhi
> India.
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