If you think it's the SVC, why not try taking TSM out of the picture: If you use OS tools to COPY a big chunk of data (say a 20 GB file) from one spot behind the SVC to the other, and time it, what is your MB/sec rate?
On 7/1/08, Thach, Kevin G <[EMAIL PROTECTED]> wrote: > > Hi all- > > > > For quite some time now, I have been trying to track down an elusive > bottleneck in my TSM environment relating to disk-to-tape performance. > This is a long read, but I would be very greatful for any suggestions. > Hopefully some of you folks much smarter than me out there will be able > to point me in the right direction. > > > > If any other LTO3 or LTO4 users out there could give me some examples of > their real-world performance along with a little detail on their config, > that would be most helpful as well! > > > > My current environment consists of: > > > > * TSM server = p570 LPAR w/4 1.9GHz processors and 8GB RAM, (6) > 2Gb HBAS (2 for disk and 4 for tape traffic), and a 10Gb Ethernet > adapter. > > * TSM 5.4.1.2 on AIX 5.3 TL6 > > * 3584 w/14 LTO3 drives at primary site > > * 3584 w/12 LTO1 drives at DR/hotsite (copypool volumes are > written directly to this library via SAN routing) > > * DB (80GB -- 4GB DBVOL size) residing on IBM DS8300 behind IBM > SVC > > * Log (11GB - single LOGVOL) residing on IBM DS8300 behind IBM > SVC > > * Primary Storage pool in question (2.5TB -- 20GB volume size), > DISK device class, residing on IBMDS8300 behind IBM SVC > > > > I currently back up about 4.5TB / night, of which ~2TB is written > directly to my primary LTO3 tape pool with a simultaneous write to my > copypool across town. So, each morning I'm left with about 2.5TB of > data to copy and migrate from my disk pool(s) to copypool and onsite > tape respectively. > > > > My backup stg performance to LTO1 tape (copypool) is about what I would > expect. I run 5 threads for this process (5 mount points used), and I > consistently average 20-25MB/sec/drive. Fair enough. I don't know of > anyone getting a whole lot more than that out of an LTO1 drive. > > > > After that is complete, I then migrate that data to my LTO3 tape here > onsite. That performance is pretty lousy compared to what I would > expect to get out of LTO3. I run 6 migration threads (6 mount points > used), and I average around 25MB/sec/drive going to LT03 as well. > > > > All SAN links between the TSM server and the LT03 drives are a minimum > of 2Gb, so that is my lowest common denominator. I've tried using less > threads to see if perhaps I was saturating an HBA rather than the drive. > Same speed. I've tried separating my DB and STG pools on different > storage subsystems. Same speed. I've opened PMR's with IBM support, > and they have poured over all of my TSM server settings / config and > found nothing to go on. We've had IBM ATS teams evaluate the situation, > and they've never been able to pinpoint a problem. > > > > I've tried various tools--tapewrite, nmon, filemon, etc. and I've not > found a smoking gun. > > > > At this point, my gut is that SVC is the bottleneck, but for those of > you familiar with SVC, you know that trying to obtain meaningful > performance statistics on the SVC cluster itself is frustrating. > > > > I know there are folks out there getting much better performance out of > LTO3 drives, so please tell me how you're doing it! > > > > Suggestions? Questions? > > > > Thank you! > > -Kevin > > > > > > > > > ----------------------------------------- > This E-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION > intended only for the use of the Individual(s) named above. If you > are not the intended recipient of this E-mail, or the employee or > agent responsible for delivering it to the intended recipient, you > are hereby notified that any dissemination or copying of this > E-mail is strictly prohibited. If you have received this E-mail in > error, please immediately notify us at (865)374-4900 or notify us > by E-mail at [EMAIL PROTECTED] >
