ADSM-L

Re: Production NetWare client down and cannot restore 5GB

1999-07-21 13:31:04
Subject: Re: Production NetWare client down and cannot restore 5GB
From: "Purdon, James" <james_purdon AT MERCK DOT COM>
Date: Wed, 21 Jul 1999 13:31:04 -0400
Hi,
  I had a client in this situation on an IRIX system.  Here are the steps I
suggested to resolve the problem:

1. Disable scheduled backups for the client machine while you're doing the
restores - it will only cause you grief.
2. Do a dsmc query backup subdir=yes for each client filespace that needs
restoration and direct the output to a file.  The time it takes this query
to complete will be the minimum time you can expect the recovery to take,
and it will give a list that you can use in step 3.
3. Use the list from step 2 to set restore priorities.  Try to set your
priorities so you are restoring shorter directory trees with fewer files
first.  Save the deep directory trees with lots of files for later. Solicit
client input and negotiate: Maybe the client doesn't need access to all of
that million-file directory tree immediately, just a few key files.
4. Begin the restores and run them in the order you determined in step 3.
Run only one restore at a time unless you have multiple CPUs,  really good
I/O to the database, and are certain that the files to be restored by each
process are not co-located on the same tape.  Running simultaneous queries
only increases database look up time, reduces network bandwidth (unless you
have really slow tape and disk drives), and causes grief if the files
required be each restore process are all on the same tape.
5. As the restore process procedes, keep the client informed.


As a data point for you, it took us approximately 8 days to restore 250 Gb
representing 250,000 files to a Cray J90 filesystem mounted via NFS on the
ADSM server. As a second data point, it took us about 24 days to restore 50
Gb representing around 2 million files over a 100 Mbs (FDDI) network to an
SGI Origin 2000.  These are both with 2.x clients....

Good luck,
Jim

> ----------
> From:         Joshua Bassi[SMTP:jbassi AT GLORYWORKS DOT COM]
> Reply To:     ADSM: Dist Stor Manager
> Sent:         Wednesday, July 21, 1999 9:58 AM
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      Production NetWare client down and cannot restore 5GB
>
> All,
>
> A member of my team is at a customer site trying to restore 5GB of data on
> a
> NetWare client.  He was called in to do a V2 to V3 upgrade and performance
> tuning, but when he got in there he was greeted with a production box
> restore that wasn't going well.  As a matter of fact it wasn't going at
> all!
>
> In the last 48 hours they have only been able to restore 1.3GB of the 5GB
> backed up.  The syntax of the original command ran was "restore
> machine_name/dnc: -su=y -replace=no".  Unfortunately the restore is moving
> unbelievably slow!  At first it was like 1.5 seconds per file comparison
> and
> subsequent restore, now it's up to 5 minutes just to compare a single file
> regardless if it's restored or not!
>
> I recommended that he generate a list of the subdirectories that needed to
> be restored and then run multiple restores with less files per restore
> stream (or even run just one stream and hopefully it'll be faster than 5
> minutes per file restored!)  That seemed to work for a while, but then
> after
> restoring a thousand files or so, it bogged way down again.  There is only
> a
> total of 170,000 files to be restored - not a whole lot.
>
> They have tried rebooting the NetWare box but that didn't help.  We aren't
> CPU-bound on the client either.  The mainframe folks indicate they are
> running business-as-usual and the networking folks indicate that the
> network
> isn't saturated at all.  We tried changing some performance tuning parms
> via
> the performance tuning guide; it helps a little, but it's not still not
> processing fast enough.
>
> The biggest problem is that they were running a really old client code -
> 2.1.0.1G!  I recommended that they download both the latest V2 & V3
> clients
> for NetWare and have them on hand ready for a possible upgrade if nothing
> else works.  Installing the V3 client would buy us the "No Query Restore",
> but I don't think that would help us due to the fact that the restore
> starts
> okay, but then for some reason bogs down after restoring x number of
> files.
>
> Any recommendations I haven't already tried?  What client would be better
> to
> install at this point: V2 or V3?  Any help would be greatly appreciated.
>
> NetWare 4.11 client 2.1.0.1G
> OS/390 (not sure what version) server 2.1.0.6 STK 4480 tape drives
> TCP/IP communication (not sure what version)
>
>
> Joshua S. Bassi
> Storage Management Team Lead
> AIX / ADSM Certified Specialist
> Dickens Services Group
> (404) 386-9848
> jbassi AT gloryworks DOT com
> www.TeamDSG.com
>