ADSM-L

Re: I don't think she can hold much more Captain! She's gonna blow!(IBM LTO Tape)

2001-08-28 19:08:37
Subject: Re: I don't think she can hold much more Captain! She's gonna blow!(IBM LTO Tape)
From: Steve Bennett <steve_bennett AT ADMIN.STATE.AK DOT US>
Date: Tue, 28 Aug 2001 15:13:09 -0800
I am not familiar with your tape units but when I started using Exabyte
Mammoth2 scsi drives and tapes, 60gb native, 150gb compressed I saw
exactly the same thing. Then the hammer dropped! I started getting some
fsr (forward search record) errors. In compressed mode the tapes were
able to hold more blocks of data than the the scsi command set could
count in it's 3 byte counter. My data was being lost along the way. The
problem is now documented and will be fixed in a future release. The
only work around was to use non-compressed format. In my case, format is
M2 instead of M2C.

If this is also your problem you need to correct it pronto because your
tpe storage pool is losing client data!


Jim Taylor wrote:
>
> How much can these 100GB native tapes hold?
>
> Can I really be getting this kind of compression?
>
> Half a TB on one tape?  Anyone else seeing this?
>
> My real issue is with the Status.  It says that the tape is still filling,
> yet its Pct Util is only at 95%.
>
> I don't get this.  I thought that a tape get to 100% full and the Est Cap
> keeps increasing until EOT is met.  At which time the Status changes to Full
> and the Pct Util can then drop from 100% as the data on the tape expires.
>
> Have I been wrong???
>
> tsm: TSM-D2>q vol
>
> Volume Name               Storage      Device      Estimated    Pct   Volume
>                           Pool Name    Class Name   Capacity   Util   Status
>                                                         (MB)
> ------------------------  -----------  ----------  ---------  -----
> --------
> /tsm/tsmstg/disk-vol01    DISKPOOL     DISK          5,000.0   30.5  On-Line
> A00000                    TAPEPOOL     LTOTAPE     100,000.0    7.2  Filling
> A00007                    TAPEPOOL     LTOTAPE     204,800.0    2.6  Filling
> A00023                    TAPEPOOL     LTOTAPE     384,482.9   65.0    Full
> A00031                    TAPEPOOL     LTOTAPE     398,471.2   64.4    Full
> A00035                    TAPEPOOL     LTOTAPE     537,664.2   85.3  Filling
>
> tsm: TSM-D2>
>
> > Jim Taylor
> > Senior Associate, Technical Services
> > Enlogix
> > *  E-mail: jtaylor AT enlogix DOT com
> > *  Office: (416) 496-5264 ext. 286
> > * Cell:  (416)458-6802
> > *   Fax: (416) 496-5245
> >
> >

--
Steve Bennett, (907) 465-5783
Steve Bennett, (907) 465-5783
State of Alaska, Information Technology Group, Technical Services
Section
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