I have a very high performance RAID system and a SAN file system that under normal circumstances performs at very high rates. However, it can't seem to keep data flowing to a bank of six LTO 3 tape drives and the best I can tell it's because of the way BE reads data from RAID. How do I set block/transfer sizes on the RAID side under BE such that it efficiently moves data to the tape drives? It appears that BE makes 64K requests which is inefficient. How can I raise that to a 1MB or more?
Are you doing B2D2T, or just backing up the Disk drives?
From the devices tab, right click on eof hte tape drives and select Properties. What are the settings for Block SIze, Buffer Size and Number of buffers?
Just disk to tape. I have experimented with a variety of settings starting with default all the way to maxing out the drive parameters but regardless of the settings, the block requests to the RAID end up being 64K. I need more like 1MB requests. The end result is that it appears as though the tape drives are starving.
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Feeding 6 LTO-3 drives at full transfer rate is quite an (exspensive) challange. You really need to multiplex data from differnet LUNS/HBA's/disk controllers, to make it work, and Backup Exec can't multiplex.
