Veritas-bu

[Veritas-bu] LTO drive won't run at full speed

2003-08-14 17:19:53
Subject: [Veritas-bu] LTO drive won't run at full speed
From: jon_bousselot AT sd.vrtx DOT com (Jon Bousselot)
Date: Thu, 14 Aug 2003 14:19:53 -0700
I believe this has been mentioned here before, and I've experienced this 
myself.  The LTO drives on our backup system are SCSI connected.  On at 
least two occasions, the scsi bus has experienced some kind of  
disruption to cause it to slow down to SE speeds.  When I could normally 
get 20+ MB/sec, the affected drive would not write at speeds above 5 
MB/sec.  Rebooting the server fixed the problem.  If this happens 
frequently, then it's likely a hardware fault.  I was able to confirm 
the slowdown by checking the system logs or dmesg.  It would clearly 
show the scsi bus error, the devices affected, and would give the exact 
speed or mode that the card was now operating.

-Jon


> One of our seven LTO drives will not read or write above 1.6 MB/sec.  
> In fact, it stays at exactly 1.6 MB/sec while in use.  Our other 
> drives average 10MB/sec, and spike up to 20+ MB/sec.  I replaced the 
> drive, with no effect.  We are using NetBackup datacenter 4.5 on a Sun 
> V880 running Solaris 8.  If it's not the drive, where should I 
> start checking for the error - media server, robot, or cables between?
>  
> Thanks
>  
> Alec Browne
> Systems Administrator
> The Institute For Genomic Research





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