Charles,
There are some other limiting factors you must consider. Although you
have 300+ clients how many do you schedule to back up at the same time?
Even if it is all of them what is your Maxsessions and MaxSchedsessions
values? If I remember right you are running on a p630 that box can
probably handle (depending on the amount of memory, # of NICs and # of
processors) up to 200-300 concurrent sessions, but you probably have it
set much lower. As with all things in life there are practical
limitations, 1200 volumes might seem to be a lot but I have worked in
large environments with several hundred volumes because that is what the
environment needed! Another question are all of these clients going to
one disk pool and/or are some going straight to tape?
On another note that I did not address in my previous post, the original
topic was about SATA drives and their viability in an ITSM disk pool. A
couple things to consider here:
1. They are cheap so you can afford to have very large disk pools -
Thats a good thing!
2. SATA drives are typically large capacity (250GB and above) when
used by IBM, EMC, LSI etc. - This is not so good, see me previous
post more dirves is better.
3. SATA drives are usually slower drives, 7200 or 10K rpm, FC drives
can 15K rpm - Another performance hit.
4. The reliability, i.e. failure rate, is not as good, but this might
not be as important in a ITSM server as it might be in a
prodcution DB server.
5. In order to get good performance out of SATA you need to work a
little harder and you probably want to go with RAID 10 or 50 to
get the best performance/reliabilty.
6. If you have to move huge amounts of data on a daily basis with a
minimal amount of time, i.e. you need the best possible
performance, than SATA is not your answer!
7. But if you need large disk pools with reasonable performance at a
great price than your going to love SATA.
Good Luck and let us know how it turns out
--
Regards,
Mark D. Rodriguez
President MDR Consulting, Inc.
===============================================================================
MDR Consulting
The very best in Technical Training and Consulting.
IBM Advanced Business Partner
SAIR Linux and GNU Authorized Center for Education
IBM Certified Advanced Technical Expert, CATE
AIX Support and Performance Tuning, RS6000 SP, TSM/ADSM and Linux
Red Hat Certified Engineer, RHCE
===============================================================================
Hart, Charles wrote:
Fantastic Read!!!! Thank you very much for the info! Just one of our TSM
server has 300+ Clients, currently using collocation and a client setting of
Resource of 4 we could potentially have to create 1200 volumes on Disk?
Regards,
Charles
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] Behalf Of
Mark D. Rodriguez
Sent: Monday, November 15, 2004 1:58 PM
To: [EMAIL PROTECTED]
Subject: Re: TSM and SATA Disk Pools
OK, so there seems to be some interest in how to layout disk pools on an
AIX system using JFS2 instead of raw lv's. I will try to keep this as
general as possible so please remember you must make some choices based
on your particular environment.
* In general I would rather have more small disks than a few large
as you will see. However, this would not apply if the larger disk
where 15K rpm vs. smaller disks of 10K rpm.
* Creating your hdisks - there are several possibilities here
depending on you environment.
o Small environments with only a few disk should use JBOD.
obviously you give up some safety over running RAID 1, 5 or
10 but small environments can't afford this anyway.
o Mid size and above should use one of the following configs
that fits there environment the best. If you will use RAID
5 then create several small arrays, 4 or 5 disks per array
is good if you have lots of disk then you can go as high as
8 per array. If you have a very large number of disks than
you can use either RAID 0 or 10, obviously RAID 10 will give
you some disk failure protection but at the cost of 2 x
actual space vs. usable space. Again 4 or 5 disk arrays (8
or 10 if RAID 10) will work well and as before you can go
larger if you have a very large number of disks to work with.
o The idea of using small arrays is so that you wind up with
as many hdisk's as possible. I like to have at least 4 or
5, but I have also worked in environments with over 50
hdisks each of which was a RAID array.
o NOTE: This section assumes you are not using any disk
virtualization. In virtualized environments you could have
logically created 4 disk arrays but physically they might
all be on the same set of disks. That situation could cause
some performance issues. Disk virtualization is way outside
the scope of this note.
* Create a VG from all the hdisks above, nothing tricky here.
* Create a JFS2 large file enabled file system on each disk. Make
sure the file system consume the entire hdisk and that it does not
span multiple disks. Any reasonably skilled AIX admin can do this
for you. In regards to the log file for these file systems for
absolute maximum performance you could dedicate a separate disk to
handle the logs, but in most cases simply selecting "in line" log
will do fine.
* NOTE: This is very important make sure that you add the mount
option of RBRW to each of these file systems. Also, it would help
to add this mount option to the file systems that contain your
ITSM DB and LOG. This option increases the I/O performance and
reduces the load on the system. You will also see a radical
reduction in system non-computational memory usage. Which means
you can use more memory for DB and LOG pages as well as for
network performance. For a more in depth discussion of this
option please refer to the AIX Performance Management Guide.
* Now create the storage pool volumes. The size of these volumes is
somewhat up to you, but I like to make sure that I have at least
as many volumes as I might have backup sessions writing to this
disk pool at any given time. That is because each backup session
(remember a client could have multiple session) opens a volume for
its exclusive use. Therefore if I have enough volumes they can
all run at once. NOTE: Again this is very important, when you
create your volumes for the storage pool make sure you use a round
robin approach to using the hdisks, i.e. if you have 10 hdisks
then create the first on hdisk1, second on hdisk2, third on
hdisk3, and so on so that 11th would be back on hdisk1. And you
must create them in sequential order! The reason for this is that
ITSM appears ( I have never seen the code nor have I had any
developers confirm this, although they all agree it appears to do
this) to use the volumes in the order they were created.
Therefore, I am sure that once a backup starts I will get all of
my hdisks in the game and the same thing will apply on migration.
* Some simple tunable system parameters, please note that when you
begin to do performance tuning you should know what you are doing
if you don't then get someone that does because you can cripple a
system if you are not careful. Having said that, you should
definitely adjust the min/max read ahead values
(j2_minPageReadAhead and j2_maxPageReadAhead) with the ioo command
a good starting point is 16/128. If you use the RBRW on the file
systems you won't need to make changes to minfree and maxfree
despite what some of the literature says you need do when you
increase the page ahead value. Minperm and maxperm parameters
have been talked about on lot on this list, but again if you are
using the RBRW mount option these values will have a marginal
effect since most of your non-computational memory usage will be
released immediately (without the use of the LRU). However, it
won't hurt any if you lower maxperm to 60% with the vmo command so
that you make sure that you have plenty of memory for
computational pages, i.e. ITSM DB and LOG pages as well as network
memory usage.
* One area of tuning that I can't cover here is tuning the path to
your disk and tape drives. There is just to many combinations
possible (SSA, SCSI, FC, iSCSI, etc.) to give any input. However
it is important that you address the performance issues of these
various communication paths. I will mention a couple of common
problems. Make sure that you don't overload you particular bus
technology, i.e. you can't put 6 LTO1 drives on the same SCSI
bus. So make sure you know the bandwidth of you bus and don't
overload it! Another common mistake is in FC environments, don't
have disk I/O traffic and tape I/O running over the same HBA this
just causes horrible performance and there is no amount of tuning
that can fix it! You must use separate HBA's and zone your switch
to make sure that traffic stays separate. SSA loops should have
at least 4 initiators, i.e. use at least 2 SSA cards on each loop,
and make sure that the SSA cards are connect as far away from each
other in the loop as possible.
* Some ITSM tunables. for the ITSM DB and LOG pages make sure you
have set BufPoolSize and LogPoolSize large enough so that you are
getting at least 99% Cache Hit Pct. on the DB and that your Log
Pool Pct. Wait is 0. Your MoveBatchSize and MoveSizeThresh should
be set to the max values, this will help things like migration and
storage pool backups.
This is a very general list of things you can do, but if you take these
guidelines and apply some common sense about your particular environment
I am sure that you can get very good performance out of your disk/tape
subsystems.
If you have any questions or comments on this than post them and lets
keep this discussion going.
--
Regards,
Mark D. Rodriguez
President MDR Consulting, Inc.
===============================================================================
MDR Consulting
The very best in Technical Training and Consulting.
IBM Advanced Business Partner
SAIR Linux and GNU Authorized Center for Education
IBM Certified Advanced Technical Expert, CATE
AIX Support and Performance Tuning, RS6000 SP, TSM/ADSM and Linux
Red Hat Certified Engineer, RHCE
===============================================================================
Wells, William wrote:
I would be interested in your post.
-----Original Message-----
From: Mark D. Rodriguez [mailto:[EMAIL PROTECTED]
Sent: Sunday, November 14, 2004 5:49 PM
To: [EMAIL PROTECTED]
Subject: Re: TSM and SATA Disk Pools
Charles,
I may be missing something here, but even your numbers out of the
Symetrix seem pretty bad. Are you sure you didn't drop a "0"
somewhere? I have one customer that I set up using SSA drives with JFS2
filesystems and LTO1 drives and we average between 35 and 40MB/sec. and
some days as high as 45MB/sec (compression of data plays a large
factor). Your Symetrix at 40GB/hr is only 11.11MB/sec! BTW, this is
with no unusual tuning to the system, since this was more than enough
performance for their needs. With a little more tuning I could easily
increase that by 50% and possibly double it if I really tried and that
is ancient SSA technology. FC technology should be much faster.
I know there are many people who prefer raw lvs for there disk pools,
but on an AIX system I don't believe it is worth it. I have never had
anyone show me raw lv numbers on AIX that I could not match (with far
less hassle) with a good JFS2 configuration. If raw is the way you want
to go than I wish you luck. However, if you are interested in switching
to using a JFS2 approach I would be glad to post to the list some simple
guidelines for configuring your environment to get much better
performance than you are reporting in your post.
--
Regards,
Mark D. Rodriguez
President MDR Consulting, Inc.
============================================================================
===
MDR Consulting
The very best in Technical Training and Consulting.
IBM Advanced Business Partner
SAIR Linux and GNU Authorized Center for Education
IBM Certified Advanced Technical Expert, CATE
AIX Support and Performance Tuning, RS6000 SP, TSM/ADSM and Linux
Red Hat Certified Engineer, RHCE
============================================================================
===
Hart, Charles wrote:
Thanks you for the link.. Good info!
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] Behalf Of
William F. Colwell
Sent: Friday, November 12, 2004 10:52 AM
To: [EMAIL PROTECTED]
Subject: Re: TSM and SATA Disk Pools
Charles,
See http://www.redbooks.ibm.com/abstracts/tips0458.html?Open
This was in a recent IBM redbooks newsletter. It discusses SATA
performance
and to me it says that the tsm backup diskpool is not a good use for SATA.
Sequential volumes on SATA may be ok.
Hope this helps,
Bill
At 10:21 AM 11/12/2004, you wrote:
Been asking lots of questions lately. ;-)
We recently have put our TSM Disk Backup Pools on Clarrion SATA.
The TSM Server is being presented as 600GB SATA Chunks
Our Aix Admin has put a Raw logical over two 600GB Chunks to create
a 1.2TB Raw Logical Volume
Right now we are seeing Tape migrations @ about 4GB in 6hrs, where before
on EMC Symetrix disk we saw 29-40GB per hour. If anyone would like to share
their TSM SATA Diskpool layout and or tips we would much appreciate it!!!
TSM Env
AIX 5.2
TSM 5.2.4 (64bit)
p630 4x4
8x3592 FC Drives
Regards,
Charles
----------
Bill Colwell
C. S. Draper Lab
Cambridge Ma.
