-----Original Message-----
From: EMC NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On
Behalf Of George Sinclair
Sent: Friday, November 24, 2006 12:30 AM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: [Networker] Question on drive target sessions?
This question concerns why NetWorker sometimes fails to start multiple
sessions on a device. I don't see this that often, but here's an
example:
I was running a group with 1 client. The client has 6 save sets. I start
the group (level full), and there's only one writable volume for the
given pool. The other is set Read-only. NetWorker loads the tape but
only sends one save set to the tape. The rest are pending. This seems
odd because the target sessions on the device was set to 5, the client
parallelism is 6 and the group parallelism was set to 0.
Anyway, it just sits there running that silly save set for the longest
time, and the rest are doing nothing. Meanwhile it keeps asking for
another writable tape. Obviously, it wants to kick of the rest, but why
the heck can't it just run some of them on the same device it's writing
the other save set to? There were no other groups running, so there's
plenty of room.
The tape library has 4 drives, and the server parallelism is set to 20
(5 per device). We're running 7.2.2 on Solaris server. The storage node
is running Linux (NW 7.2.2) and manages the library.
Now, I finally set the other tape (was read-only) to appendable. Within
30 seconds, NetWorker then stops requesting a writable tape (issues
event cleared message) and then starts to load the other tape.
However, before it loads it it then sends 4 of the remaining 5 save sets
to the device that the first one was writing to. After mounting the
other volume it sends the 6th and last save set to that device.
I suppose it's conceivable that it was just coincidence and that it took
it that long to figure out what it wanted to back up? I didn't think it
generally mattered when running fulls even if a lot of files are
involved? Anyway, assuming not, why the heck did it have to wait until
it had another appendable tape to send more save sets to the first one
if the first device was only running 1 session?
Does anyone else see this behavior ever? I ran 20 other groups today,
all with various number of clients, and I never saw this, so it doesn't
occur most of the time.
Thanks.
George
--
George Sinclair - NOAA/NESDIS/National Oceanographic Data Center
SSMC3 4th Floor Rm 4145 | Voice: (301) 713-3284 x210
1315 East West Highway | Fax: (301) 713-3301
Silver Spring, MD 20910-3282 | Web Site: http://www.nodc.noaa.gov/
- Any opinions expressed in this message are NOT those of the US Govt. -
>>>>>>>>>>>>>>>>>>>>>>>>>
I've seen this behaviour just recently, v7.3.2 on linux server.
Initially there were several savesets processing in parallel to a single
tape where as they completed none of the remaining sets waiting to
process kicked off leaving just one running. I did not provide another
tape and when the single save set completed, others were launched to the
same tape until the backup was completed. I'd manually kicked off the
group since it had not completed its normal incremental (due to
something else) and was monitoring it at the time. Since I'm running
v7.3.2, I'm expecting odd behaviour. I guess this is something that got
carried forward.
Patti Clark
Unix System Administrator - RHCT
Office of Scientific and Technical Information
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