SCSI vs SAS

R

Rossi~

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Dec 8, 2008
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Replaced a Powervault 114T (SCSI LTO3) with the 114X (SAS LTO4)
It appears that the 114X is quite a bit slower... Does this seem right to you? It was bought as a repalcement as the 114T was getting old, we needed to move to higher capacity tapes and we needed it faster. All seems like a waste at the moment.
The 114X is on the standard Perc controller that comes with the Powervault, wasn't sure whether that was the source of the problem.
 
Can a mod please move this to the backup section pretty please.

Thanks
 
What exact tape drive or drives do you have in the loader?

Is the PERC controller setup as a raid controller, or do you have the RAID turned off?

I have found in testing that you have to have the RAID portion turned off for any SAS controller to get full throughput for a SAS tape drive, in fact sometimes it wont work at all if you have RAID turned on for it. In general I recommend dedicated SAS cards for the tape drive(s).
 
It's got a pair of LTO-4 IBM HH4 tape drives in it on a Dell 5/E HBA, not the Perc.
We used to use the LTO-3 IBM drives in the 114T on the onboard SCSI 320 controller in a Dell PV1950
 
What kind of speeds are you seeing?

What type of software are you using for backup?
 
Using Symantec Backup Exec 12.5. Found where the problem is, but unable to find a resolution... Basically it's backing up 7 servers and seeing speeds of 2,520MB/Min which is great and what i want to see, but one of the servers it only doing 71MB/Min ....... which is soul crushingly slow. I can't seem to find out why. All the servers have the agents running and the same settings etc. This server is running RAID-5 and 2x1Gigabit connections for load balancing so i can't see why.
I have tried copying 500Mb from that server to the backup server and seems very quick, so physically the conenction is ok.

So basically it's not hardware related, it's software. Anything i should check on backup exec? Like maybe the "I hate Rossi" box is ticked somewhere and i just can't find it.
 
Right, running a test. Runs at 3,000 MB/Min backing up large files (PST's) and then it moves on the masses of tiny files and folders (over 2.5Million folders and small files) and it all slows down to a snails pace.. Though this never happened on the last server and i couldn't copy across the configuration so had to create a new one, so i think there is something missing that would avoid the slow down on masses of small files.
 
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Unfortunately I can not help you with Backup Exec, though I do work for a different company that makes backup software :D
 
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