I'll second Mark's observations.
I'm the primary sysadmin over the whole backup infrastructure at
our company. We have TSM running on various platforms depending on the
location and the volume of data. Currently we have 15 servers in total,
with some AIX/pSeries, Windows/Intel & Solaris/Sun. I won't go into
detail, as Mark described the limitations we have also encountered.
For us, the Window/Intel is good for the smaller sales offices,
where volume is low, the number of clients is <50, and the
administration of a *nix host is unavailable. The Solaris/Sun
combination seems to work well in our mid-range sites, such as design
centers, but that solution was put in primarily because of the staff at
those sites were ~only~ familiar with Solaris. At our largest locations,
corporate offices & manufacturing sites, the AIX/pSeries is our
workhorse. We have 6 TSM servers at our corporate site that each process
about 3TB of data a day, with most of that happening in the 14 hour
backup window (when we ~prefer the backups to happen if at all
possible).
The AIX/pSeries combination just seems to be able to handle a
higher and heavier I/O load than any of the other combinations we have
in production. I'm not sure if the OS or the hardware deserves more of
the credit. Perhaps it's because TSM/AIX/pSeries all come from the same
vendor so they seem to be integrated better. I'm not saying that IBM is
a perfect company, but it sure is nice to open 1 case for TSM server
performance problems and get very little finger pointing (a situation we
often encounter when opening up cases with our Sun and Windows TSM
servers.)
Just my 2-cents,
Ben
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Mark D. Rodriguez
Sent: Wednesday, November 09, 2005 12:30 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: Platform change to Windows?
Tab,
Personally I prefer AIX. And I know there are going to be some Windows
bigots who disagree with everything I say about Windows, so I am going
to qualify my remarks by saying that as a consultant I have worked in a
wide variety of environments from small to large with all different
flavors of OS's so my comments are based on my experiences. But having
stated that, let me offer a few things for you to consider. First I am
going to discuss the Windows environment using 32 bit Windows which will
have some serious limitations. I believe that is what you are intending
to do since you didn't specifically state other wise.
One major problem is that W2K3 does not have good memory management, in
fact the TSM server process will only be able to see/use 4GB of memory.
That means any memory beyond 4GB is not used at all by TSM, however if
you are running multiple instances of TSM or you are running the ISC/AC
on the machine it maybe useful to have more memory. Now back to the 4GB
memory for the TSM server, 2GB is used by the kernel right off the top,
which means that you can only get about 1GB for the BUFPOOLSIZE. The
rest is needed by the the TSM server code and any other overhead
required by the process. If your DB requires a larger BUFPOOLSIZE to
perform well you may be out of luck!
Another thing to consider is concurrent I/O (network and disk), Windows
based machines as you stated a clearly lacking in this area. I notice
it particularly when I am trying to backup many nodes at the same time.
Once I get above 20 to 30 sessions I start to notice that my "Pct. Comm.
Wait Last Session" values start to go very high even though the overall
bandwidth is not maxing out the network connection, i.e. 30-40 MB/sec
across a 1Gb network. Where as on a comparable AIX system I can run 3
or 4 times the number of sessions with no noticeable degradation in the
Comm. Wait times. This is mostly due to poor TCP/IP performance of
Windows based machines, single sockets are fine but open 30 sockets and
try to pipe data through them and you will be slow!
Now lets talk about disk I/O. One thing the Windows version of TSM has
going for it is that it is very quick to build DB, LOG and Diskpool
volumes. This is because it doesn't initialize them like it does on AIX
which can take quite a while if you are building large volumes, but how
often are you really creating these volumes. Disk I/O performance to
like SAN hardware is pretty close in both machines. However, again when
doing many current data streams the AIX environment always outperforms
the Windows one. Not as big a difference as the networking issues but
still noticeable.
Performance monitoring and tunning is another area of concern. There
are reasonably good monitors for both environments. No matter whether
it is memory, network or file I/O performance tuning in an AIX
environment is much more flexible and far easier to do. To be fair,
Windows in small environments often performs quite well with no
extraordinary tuning required. AIX on the other hand usually will
require some tuning to get it to perform well. In larger environments
AIX will require a bit of tuning to make sure it is running optimally,
but for Windows there just doesn't seem to be enough tuning to get it
running as well as it should in large environments.
In summary I will say that Windows based machines are fine for small to
medium size environments. When you get to the top end of the medium and
into the large environments I think you should consider a machine that
can handle the kind of I/O you are needing to pump through it. I think
from the description of your environment that you are a medium size
environment, but like everyone else you are probably growing. You might
want to consider this that for the price of a Quad Xeon system you could
easily afford to get a new 2-Way P5 (i.e. a P5 520) which would clearly
out perform the Xeon based machine. Also, the P5 520 would allow for
future growth.
--
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
========================================================================
=======
Tab Trepagnier wrote:
>We are considering migrating our TSM systems from AIX to Windows 2003.
>
>I know that the experience of the forum participants is that AIX
>provides superior I/O performance, but where is that threshold?
>
>These are our system details. I'd like for anyone with experience with
>a system of similar size to share their experiences regarding Unix vs.
>Windows.
>
>We are currently running TSM 5.1.10 on a 2-way 6H1 with 4 GB RAM.
>We are considering running TSM 5.3.2 on a 2-way or 4-way 3.0 GHz Xeon
>with
>4 GB RAM. All non-OS I/O would be via GigE network and redundant 2 Gbs
>fiber.
>
>TSM system details:
>
>DB: 32 GB @ 83% utilization
>Log: 5 GB, roll-forward mode
>Primary data: 16 TB with one copypool (another 16 TB to manage)
>Nodes: 175 backing up during a 10-hour window
>Average daily incoming data: ~ 200 GB; may be reduced via deployment
of
>TDP Oracle
>Disk: 1 TB DAS, 3 TB SAN
>Tape: LTO-1, DLT8000, 3570XL, four SCSI drives each; libraries will
be
>consolidated
>Daily copypool updates sent to vault
>Semi-annual exports in the 2-5 TB range
>
>Does that sound like a system that could reasonably be hosted on a
>modern Windows system? Is a 2-way adequate, or should we get a 4-way?
>
>Thanks in advance.
>
>Tab Trepagnier
>TSM Administrator
>Laitram, L.L.C.
>
>
>
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