You should investigate the latest LTO2 firmware, 53Y2L2F.ro

Our drives were all at 4772 and we were having a variety of problems (much
better than 38D0).

Since I upgraded to 53Y2, things have calmed down quite a bit.




Matthias Feyerabend <M.Feyerabend AT GSI DOT DE>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
07/06/2005 01:49 PM
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"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>


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Re: [ADSM-L] Very slow restores (days), hours to locate files






You are at which firmware on IBM LTO2 FC ?
We had last year big problems with firmware 38D0 , until we switched to
4770.
You can see that problem if you use tapeutil and skip to EOD and see how
long it takes.
Should be some minutes, was with our firmware one hour and more.
Just a guess.

Regards Matthias

Robin Sharpe wrote:

>Hi guys,
>
>We're having problems restoring some windows servers (W2K)...
>The servers in question had some disk problems and are being rebuilt, so
>the Windows admins are restoring the C: drive.  It is an 8GB drive and
less
>than 50% used, so only 4GB to restore.  It has taken several days to
>restore.  I know one of our problems is that the data is spread over
>hundreds of volumes (literally... I counted 310 from a volumeusage
query).
>Another problem is that we have an overflowed library, but we have loaded
>all of the tapes from the Windows storage pool.  What I don't understand
is
>why it takes so long to locate a file once the tape is mounted.  We have
>seen the same tape mounted for hours before any data is transferred. Here
>is an excerpt from a "q se f=d" of a restore that is running right now:
>
>               Sess Number: 1,143
>              Comm. Method: TCP/IP
>                Sess State: Run
>                 Wait Time: 0 S
>                Bytes Sent: 670.9 M
>               Bytes Recvd: 58.2 K
>                 Sess Type: Node
>                  Platform: WinNT
>               Client Name: WANO01
>       Media Access Status: Current input volume(s):  200658,(2279
Seconds)
>                 User Name:
> Date/Time First Data Sent:
>    Proxy By Storage Agent:
>
>This restore has been running for almost 12 hours now (they have been
>restarting them periodically).  There has been NO DATA transferred from
>that tape in the 38 minutes it has been mounted... I know this from doing
>an lsof command and looking at the offset which indicates the number of
>bytes transferred.
>
>I know that when I restore a single file, it can be found within seconds
of
>mounting a tape (these are all LTO-2)... so, why does it take so long in
>this case?  Is TSM actually reading the entire tape?  If so, wouldn't I
see
>lots of data being transferred?  Or is there some kind of SCSI command
that
>allows the drive to read and compare the data it gets?  I thought TSM
>stored actual locations of the files in the DB, so it could quickly find
>any file (or aggregate) without reading the whole tape... I've been
>searching the literature, and I can't find any details on this.
>
>The TSM server is on HP-UX 11i, IBM LTO-2 drives, fiber attached, in a
STK
>L700 library.  Also, my DB is huge (314GB), and we are currently (for the
>last year) unable to delete anything, so we have many versions of
volatile
>files.  We are planning to split our environment into several TSMs, and
in
>the short term, our windows admins will start doing weekly selective
>backups of the C: drives to consolidate active versions on few tapes.
>
>Thanks for any thoughts on this....
>
>Robin Sharpe
>Berlex Labs
>
>
>

--
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Matthias Feyerabend                                              |
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