Networker

Re: [Networker] How to get around block size errors?

2005-11-17 19:55:37
Subject: Re: [Networker] How to get around block size errors?
From: Matthew Huff <mhuff AT OX DOT COM>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Thu, 17 Nov 2005 19:53:32 -0500
 
When I've seen that error, usually I've traced it down to an actual SCSI
error. Check your messages log file, and make sure that your st driver
has max error logging on. What adapter are you using on the storage
node?

--
Matthew Huff           | One Manhattanville Rd
Director of Operations | Purchase, NY 10577
OTA LLC                | Phone: 914-460-4039 
mailto:mhuff AT ox DOT com    | Fax:   914-460-4139   
-----Original Message-----
From: Legato NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU]
On Behalf Of George Sinclair
Sent: Thursday, November 17, 2005 7:44 PM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: [Networker] How to get around block size errors?

Is there any recommended way to recover data when you get a block error
during nwrecover?

nsrd: media notice: Volume "volname" on device
"rd=storagenode:/dev/nst2": Block size is 512 bytes not 65536 bytes.
Verify the device configuration. Tape positioning by record is disabled.

At that point, the recovery just hangs as the tape sits idle. We see
this a lot. Sometimes, the error occurs during backups and sometimes
during recoveries, but not always. Seems random., but seems to occur
about 40% of the time we need to recover data. Yikes!!!

Whenever I've scanned one of these tapes, to see the actual block size,
the reported block size is always what NetWorker *wants* or is
expecting, not what it complained about. The LTO 1 tapes are always 64
KB and the SDLT 1 tapes are always 128 KB. Also, checking the devices
under the GUI shows these respective sizes. Not sure why NetWorker is
getting confused.

Is there anything that can be done to at least temporarily allow you to
get around this problem? Anything to provide relief other than to pack
up and move away to a far off land with no supper?

We were told by Legato tech support (we sent them our log files) that
engineering said there were issues that were fixed in later releases,
but no clearer answers beyond that -- nothing specific regarding the
actual block problems/errors themselves and how to resolve them. We have
received a new media kit (7.2.1) and plan to migrate to a new server to
run this, but we can't do it for a few more weeks. Has anyone seen the
same problems go away after upgrading to a more recent release? I know
there have been a lot of reported block problems with Windows OS.

Currently, we're running an old release 6.1.1 on Solaris 2.8. but the
devices we're using are managed by a single RedHat Linux storage node
(6.1.1). The devices are SDLT 1 and LTO 1 drives. The storage node has 2
libraries, one with LTO drives, one with SDLT. We've seen these problems
on all the devices, though, and I think this problem has been persistent
for a long time. We use LSI logic SCSI cards. We're using Fuji and
Maxell tapes.

We have what we think is a properly configured stinit.def file (see
below), but if there's anything we can do in the mean time to provide
some relief, with minimal impact, or anything we can try, that would be
nice. I hope these problems go away with the new release. I wonder,
though, about accessing tapes that were labeled and written with our
current release?

# Seagate Ultrium LTO
manufacturer=SEAGATE model = "ULTRIUM06242-XXX" {
scsi2logical=1 can-bsr auto-lock
mode1 blocksize=0
}

# SDLT220
manufacturer="QUANTUM" model = "SuperDLT1" {
scsi2logical=1
can-bsr=1
auto-lock=0
two-fms=0
drive-buffering=1
buffer-writes
read-ahead=1
async-writes=1
can-partitions=0
fast-mteom=1
#
# If your stinit supports the timeouts:
timeout=3600 # 1 hour
long-timeout=14400 # 4 hours
#
mode1 blocksize=0 density=0x48 compression=1    # 110 GB + compression
mode2 blocksize=0 density=0x48 compression=0    # 110 GB, no compression
}


Thanks in advance.

George

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