Well, a) Large servers with small filesize should always go to a random diskpool. Sending them to tape (or a sequential filepool) will most certainly reduce performance. So NO, keep sending those small files to a random disk pool. If it's not big enough, increase the size, dont try sending the data somewhere else.
b) For ALL storage pools, there will be 1 migration process per node. It doesnt matter if it's random, sequential or a CD. It's always gonna be 1 process per node. c) Migration processes is usually not the issue. The issue is somewhere else. So dont get blind on the 1 migration process per node. If you're having performance issues, it's most likely not the migration process. d) If you get I/O wait, the disks containing your disk pools is most likely not properly configured. Remember that the basic idea of performance for a random disk pool is to have enough spindles (as in, having enough harddrives in whatever disksystem you're using). The only way to long-term increase the performance is to increase the amount of spindles. The disksystem's memory cache is always helpful, but when it gets filled (and it will) it will need to empty to physical spindles. If your disks cant handle that load, you have a bottleneck. e) When you increase your diskpools to 10TB, make sure that the increase is done over new spindles (harddrives) and not the same you're already using. Expanding the array/lun across the already used spindles wont increase your performance. Regards Daniel Daniel Sparrman Exist i Stockholm AB Växel: 08-754 98 00 Fax: 08-754 97 30 [email protected] http://www.existgruppen.se Posthusgatan 1 761 30 NORRTÄLJE -----"ADSM: Dist Stor Manager" <[email protected]> skrev: ----- Till: [email protected] Från: amit jain Sänt av: "ADSM: Dist Stor Manager" Datum: 03/15/2012 17:46 Ärende: Re: migration threads for random access pool and backups issue Thanks to all for these valuable inputs. Appreciate it a lot. Well this is first time this data is getting backed up. For now here is what I was not aware and what I have done: 1. On Random Access pools multiple migration sessions can be generated, only if we backup on multiple nodes ? Is my understanding correct or there is any way to increase the number of tape mounts ? Now i know: Migration processes depends on nodes. random access storage has limitation in regards to migration process. If I had more than 2 nodes backing up to the same random access storage pools then I could have more than two migration processes depending on the configuration settings. If the disk pool gets filled up, data goes to next pool and backups wont fail. As in our environment we have large small number of files so file type disk pool is not a good idea. Improving backend speed does not always work better. Because the speed coming into TSM server will not be fast enough or sometimes equal or little bit better compared to the speed dumping data from disk to tape. This all depends on the type of data to back up. If there are huge number of files, One migration process is good enough and have 2 or 3 more additional tape drives allocated to direct backup when disk pool is overflow. That was much much faster than using file type devclass with multiple migration processes. Currently able to backup ~4TB a day. I will be increasing the stg pool size to 10 TB and hope i will get better performance. These is also bottleneck from the TSM client side. Seeing IO wait from the client side. Thanks Amit On Sat, Mar 10, 2012 at 9:08 PM, amit jain <[email protected]> wrote: > Hi, > > I have to backup large data ~ 300TB and have small DISK POOL SIZE 500GB. I > have 3 filespaces, backing up on single node. I am triggering multiple > dsmc, dividing the filespace on directories. I have 15 E06 Tape drives > and can allocate 5 drives for this backup. > > If I run multiple dsmc sessions the, server starts only one migration > process and one tape mount. > As per ADMIN GUIDE the Migration for Random Access is "Performed by node. > Migration from random-access pools can use multiple processes." > > My Question: > 1. On Random Access pools multiple migration sessions can be generated, > only if we backup on multiple nodes ? Is my understanding correct or there > is any way to increase the number of tape mounts ? > > 2. The only way to speed up with current resources is to backup to File > device class, so that I can have multiple tape mounts? > > 3. Any inputs to speed up this backup? > > Server and client both are on Linux, running TSM version 6.2.2 > > Any suggestions are welcome. > > Thanks > Amit >
