Just pointing out a more common use of maxscratch that I see at smaller customers, which is in conjunction with collocation.
If you have collocation set to node (or filespace), then TSM is going to try and put each node (or filespace) on a separate cartridge. So if you have a smaller library, with 60 slots you can use for a storage pool, but 120 clients to back up, you set maxscratch to 60 and TSM will stack 2 nodes per cartridge. If you aren't using collocation, or have some other reason for limiting cartridge use, you can just set maxscratch to 9999. W -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[email protected]] On Behalf Of Thomas Denier Sent: Thursday, October 09, 2014 8:56 AM To: [email protected] Subject: Re: [ADSM-L] maxscratch If scratch tapes are also used for purposes other than storage pool volumes, such as database backups, the sum of the maxscratch values should be a bit less than the number of volumes in the library. Thomas Denier Thomas Jefferson University Hospital -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[email protected]] On Behalf Of David Ehresman Sent: Thursday, October 09, 2014 8:38 AM To: [email protected] Subject: Re: [ADSM-L] maxscratch Eric, That is correct. If you use maxscratch, it should be set to the total number of volumes you want a particular storagepool to use. If you have multiple storagepools sharing a tape library (virtual or not), the sum of their maxscratches should equal the number of volumes in the library. Using maxscratch in this way lets you forecast when you will need additional volumes. Alternatively, you can set maxscratch to a high number and not worry about it; you however lose the information about how soon you might need to add new volumes. David -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[email protected]] On Behalf Of Loon, EJ van (SPLXM) - KLM Sent: Thursday, October 09, 2014 6:54 AM To: [email protected] Subject: Re: [ADSM-L] maxscratch Hi Steven! So if I understand your explanation correctly, for a storagepool used by one server only, the maxscratch should always be equal to the total amount of volumes in this pool? So when adding new scratches, one has to raise the maxscratch with an equal amount? Kind regards, Eric van Loon AF/KLM Storage Engineering -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[email protected]] On Behalf Of Steven Langdale Sent: donderdag 9 oktober 2014 10:20 To: [email protected] Subject: Re: maxscratch Eric It's the max number of vols that can be used from the scratch pool by the particular stgpool. so in your instance (assuming you have a single stgpool with all 4000 private takes in it AND it got them from the scratch pool), if you set it to 1000 you won't be able to use anymore new scratch tapes until the usage goes below 1000. You can look as it as a way to stop a single stpool stealing all of the scratch tapes. Steven On 9 October 2014 08:53, Loon, EJ van (SPLXM) - KLM <[email protected]> wrote: > Hi guys! > I never used the maxscratch value for our VTL libraries, but I'm just > wondering how it works. > From the TSM Reference manual: > > MAXSCRatch > Specifies the maximum number of scratch volumes that the server can > request for this storage pool. This parameter is optional. You can > specify an integer from 0 to 100000000. By allowing the server to > request scratch volumes as needed, you avoid having to define each volume to > be used. > > What is meant by scratch volumes here? The total amount of scratch > tapes when you start with an empty TSM server or the amount of > scratches in the current situation? > For instance, I have a server with 4000 private tapes and 1000 scratch > tapes. Should I set it to 1000 or 5000? > Thanks for your help in advance! > Kind regards, > Eric van Loon > AF/KLM Storage Engineering > ******************************************************** > 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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