Device Management / Max parallelism NW751 Query

Question

Hi, I'm trying to understand what exactly the Max Parallelism field, in the Device Management area, in the Configuration tab, of library properties is for. Could anyone shed some light pls? Tks, Liam

ble1 · Accepted Answer

Yes (or restores). The logic behind is that you do not wish all your devices to be locked by single operation (like massive labeling) and have other jobs waiting for that one to complete.

ble1 · Answer

max parallelism is jukebox setting which is used to say how many concurrent nsrjb operation there will be. Default is total number of device -1. In example, if you have 4 drives your max parallelism will be 3. If you issue command to label 30 tapes NW will use 3 drives instead of all 4.

DavidHampson · Answer

It is the maximum number of streams of data that can be written to that device. The reason that you may want to have control over this is several streams of data going to a device will be multiplexed - they will be chopped up and written to the tape simultaneously; the more streams of data doing this, the more tape you need to read for a recovery, so you don't want this to get too high. If it is a VTL device rather than a physical device it is not going to be so significant in terms of recovery performance but you may still want to consider setting this to a reasonable value to prevent data becoming split over several volumes.

lguinane · Answer

Tks Hrvoje,So is the theory behind this that there will be devices available for saves ?Tks,Liam

lguinane · Answer

Hi David,are you confusing my question with device target sessions ?Tks,Liam

DavidHampson · Answer

Sorry Liam, I didn't realise you were referring to the library instead of the device... Hrvoje has already answered this one correctly for a library, I don't think I can improve on that one

lguinane · Answer

Tks David

benzino1 · Answer

From my experience, and to keep this in mind, setting this parameter to 1 doesn't mean that all operations on jukebox will be sequential - performed one after another.

100x · Answer

hi:What does it mean: single operation . Should not include the backup&#xa0; Operation.

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Device Management / Max parallelism NW751 Query

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