Hiya, I think I can see what you are trying to get at, but what I am curious about is whether the 20MB/s from your disks is due to a physical SCSI bus restriction, eg your disks are all attached on one 20MB/s SCSI bus, or whether your 20MB/s is a speed you've seen through some monitoring tool, as you're disks could peak at higher rates depending on the type of I/O activity.
Either way it is hard say put an estimate as to whether running two migrations will cause be "bottlenecked" by the disks. You need to take into consideration many things such as whether the data on disks is compressed from the client or not. We can access our TSM disks at around 100MB/s and can run 10 concurrent migrates to LTO1 drives, but when we have the 10 migrates running I always seem to see the disk throughput to be between 40-60MB/s, and never hitting the available throughput of the disks. Sorry that I cannot offer any specific advice, but I hope that this gives you some thoughts on the problem. Many thanks Andy Wilcox UNIX Systems Administrator Aquila Networks -----Original Message----- From: Patrick Rainer [mailto:[EMAIL PROTECTED] Sent: 03 March 2004 14:36 To: [EMAIL PROTECTED] Subject: Antwort: Re: 2 LTO-Drives Load-Balancing Hello again Sorry. Maybe my question can be wrong interpreted. For example: I have two migration processes from disk stgpool to tape drive. My diskdrives offer about 20MB/s. The question: Is the transferrate of the diskdrives split up for the tape drives to 50% for each drive? (10MB/s per drive) (Also means 50% per process) Or uses one drive the full transferrate which is possible for one drive (15MB/s) and the other drive only gets the rest (5MB/s)? My problem -> 5MB/s means permanent Stop-and-Go-mode for one drive. I would like to hear, that the TSM-server splits up the transferrate. This means each migration process/job uses 10MB/s. Thank you. Best regards Patrick Karel Bos <[EMAIL PROTECTED]> Gesendet von: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> 03.03.2004 15:04 Bitte antworten zu "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> An [EMAIL PROTECTED] Kopie Thema Re: 2 LTO-Drives Load-Balancing TSM is not load-balancing on a drive level. TSM will use multiple drives on a job level. Regards, Karel -----Oorspronkelijk bericht----- Van: Patrick Rainer [mailto:[EMAIL PROTECTED] Verzonden: woensdag 3 maart 2004 14:41 Aan: [EMAIL PROTECTED] Onderwerp: 2 LTO-Drives Load-Balancing Hello TSM users, a.a.o.o I searched the mailinglist archive and the discussion forum, but did not found a solution for my problem. We are using TSM 5.2.2.1 for library evaluation. We are testing a HP MSL5030 with two LTO1 drives. Our disks provide a datarate of about 20MB/s. LTO1 supports a datarate of maximum 15MB/s and starts STOP-and-GO-Mode at about 7MB/s. My question: Is the TSM-Server balancing the load of the two drives? That means: Every drive gets about 10MB/s Or gets one drive 15 MB/s and the other only 5 MB/s? We tried to analyze this load, but it isn't that simple. The only way is to calculate the load out of the transfered bytes and the needed time. How is it possible to monitor the load of one drive? (HP told us, we shoud check if the LED's are blinking slow or fast ?!?) 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