07-04-2014 07:42 AM
NB7601, Solaris master/media svr plus windows 2008r2 media server. The latter has 2 drives for doing ndmp backups and two for non-ndmp and is the one I have a question about. The drives are hp lto4 fibre, in a HP msl robot.
In over three years there has not been at any time a tapealert to clean a drive. I'm struggling to believe this can be real. The drives are heavily used overnight and at weekends yet not a single clean. Tapealert is enabled, there is a cleaning tape (but of course its never been requested), and I've run the robot with auto-clean both off and on ( more out of curiosity : I believe it should be off ). My other media server gets through cleaning tapes regularly though there are 10 drives in my other robot and they are IBM LTO4: the loads are similar but the 10drive robot is a couple of years older.
There are tapealert msgs in the bptm log: process_tapealert / tapealert_and_release / 0x0 0x0, which suggests its all working fine.
Your thoughts and experiences appreciated. It would be nice to be able to trigger a tapealert just to check it does do as its supposed.
TIA,Jim
Solved! Go to Solution.
07-04-2014 11:38 AM
According to this link below you may have a optimal installation where the tape drives run at designed speed, thus no need for cleaning.
LTO drives are designed to remove normal levels of contamination automatically. Small internal brushes sweep the debris away before it can build up and become a problem. So many LTO drives never require supplementary cleaning with cleaning cartridges.
http://docs.oracle.com/cd/E35103_07/en/E24606/html/get-started.htm
07-04-2014 10:37 AM
07-04-2014 10:44 AM
07-04-2014 11:38 AM
According to this link below you may have a optimal installation where the tape drives run at designed speed, thus no need for cleaning.
LTO drives are designed to remove normal levels of contamination automatically. Small internal brushes sweep the debris away before it can build up and become a problem. So many LTO drives never require supplementary cleaning with cleaning cartridges.
http://docs.oracle.com/cd/E35103_07/en/E24606/html/get-started.htm
07-04-2014 11:41 AM
Just had a look through the code.
It seems, though as you will image it is quite complex, that there is only one funcion that is used to read the tapealerts from the drive. So if you're receiving 'some' alerts, it's working.
In nutshell, the drive 'stores' the tape alerts, and NBU reads them, then clears them, on drive unload.
So, if we can read one, we can read all ...
scsi_command -d <drive path> -log_dump
.. will show the tapealert flags
Eg
***TapeAlert Page (0x2e) -- ONLY flags that are SET
(I don't have any set though)
Guess (and this is a guess...) you would have to trigger the flags (if they're going to set) by using the drive outside NBU, else on unload they are going to be cleared leaving nothing for scsi_command -log_dump to report.
So tar / cpio / dd time ...
... though, given, as mentioned the same function reads the tape alerts each time, I think this is barking up the wrong tree.
Vendor time me thinks, it's going to be quicker, even if you have to spell out tapealerts are outside NBU ...
07-04-2014 11:43 AM
... and having just seen the thread by the fabulous Nicolai, seems you might not have an issue ... I didn't know the self cleaning was that good ...
07-04-2014 05:08 PM
If you still have a doubt, check logs on MSL or try diagnostic tools(if provided by HP) on each tape drives.
07-07-2014 09:28 AM
I like your quote Nicolai, very interesting.
Jim
07-09-2014 05:04 AM
Thanks
07-16-2014 11:12 PM
Hi Jim,
Was the issue resolved? No solution has been marked.