Hello Eric, welcome to my nightmares. Take a seat, wanna have a drink?
I had the pleasure of performance and data corruption PMRs during the last two years with TDP Oracle. Yes, at first the customer got blamed for not adhering completely to to blueprints, but after some weeks it boild down to ... silence. Data corruption was because of what ended in IT28096 - now fixed. Performance is interesting, but resembles to what you have written. We work with MAXPIECESIZE settings on RMAN to keep the backup pieces small and got some interesting values, pending further observation, but we might be on a cheerful way. I'm talking about database sizes of 50TB here, warehouse style. In between we moved the big DBs to a dedicated server to prove that the performance drop is because of the big DBs, and the remaining "small" DBs - size of 500MB up to 5TB - didn't put any measurable stress on the DB in terms of expiration and protect stgpool. Even the big DBs on their dedicated server performed better in terms of expiration and protect stgpool, which might have been a coincidence of these DBs holding nearly the same data and having the same retention period. What I can't observe is a slowness of the DB. Queries are answered in the normal time - depending on the query. a count(*) from backupobjects naturally takes some time, considerably longer when you use dedup, but the daily queries are answered in the "normal" timeframe. What helped immediately was some tuning: - More LUNS and filesystems for the TSM-DB - smaller disks, but more of them, for each filesystem. changing the disks from 100GB to 2 x 50GB for each DB-filesystem got me a performance boost of 200% in expiration and backup db. Unbelievable, but true. Yes, I'm using SSD. And SVC. And multiple storage systems. Performance isn't the problem, we are measuring 2ms respone time for write AND read. - stripeset for each fileset -- Michael Prix On Fri, 2019-07-19 at 07:29 +0000, Loon, Eric van (ITOP NS) - KLM wrote: > Hi TSM/SP-ers, > > We are struggling with the performance of our TSM servers for months now. We > are running several servers with hardware (Data Domain) dedup for years > without any problems, but on our new servers with directory container pools > performance is really, really bad. > The servers and storage are designed according to the Blueprints and they > are working fine as long as you do not add large database (Oracle and SAP) > client to them. As soon as you do, the overall server performance becomes > very bad: client and admin session initiation takes 20 to 40 seconds, SQL > queries run for minutes where they should take a few seconds and q query > stgpool sometimes takes more than a minute to respond! > I have two cases open for this. In one case we focused a lot on the OS and > disk performance, but during that process I noticed that the performance is > most likely caused by the way TSM processes large (few hundred MB) files. I > performed a large amount of tests and came to the conclusion that it takes > TSM a huge amount of time to delete large deduplicated files, both in > container pools as deduplicated file pools. As test I use an TDP for Oracle > client which uses a backup piece size of 900 MB. The client contains about > 5000 files. Deleting the files from a container pool takes more than an > hour. When you run a delete object for the files individually I see that > most files take more than a second(!) to delete. If I put that same data in > a non-deduplicated file pool, a delete filespace takes about 15 seconds... > The main issue is that the TDP clients are doing the exact same thing: as > soon as a backup file is no longer needed, it's removed from the RMAN > catalog and deleted from TSM. Since we have several huge database clients > (multiple TB's each) these Oracle delete jobs tend to run for hours. These > delete jobs also seem to slow down each other, because when there are > several of those jobs running at the same time, they become even more slow. > At this point I have one server where these jobs are running 24 hours per > day! This server is at the moment the worst performing TSM server I have > ever seen. On the other container pool servers I was able to move the Oracle > and SAP server away to the old servers (the ones with the Data Domain), but > on this one I can't because of Data Domain capacity reasons. > For this file deletion performance I also have a case open, but there is > absolutely no progress. I proved IBM how bad the performance is and I even > offered them a copy of our database so they can see for themselves, but only > silence from development... > One thing I do not understand: I find it very hard to believe that we are > the only one suffering from this issue. There must be dozens of TSM users > out there that backup large databases to TSM container pools? > > Kind regards, > Eric van Loon > Air France/KLM Storage & Backup > ******************************************************** > For information, services and offers, please visit our web site: > http://www.klm.com. This e-mail and any attachment may contain confidential > and privileged material intended for the addressee only. If you are not the > addressee, you are notified that no part of the e-mail or any attachment may > be disclosed, copied or distributed, and that any other action related to > this e-mail or attachment is strictly prohibited, and may be unlawful. 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