Re: [Networker] Waiting for 1 writable volume ...
2011-07-08 13:21:29
On 07/08/11 10:11, Goslin, Paul wrote:
I would increase the drive target sessions to at least 6 as 4 seems awfully
low. That may be enough to stop the requests for additional volumes... It
sounds like it's attempting to run more concurrent streams than your drives are
configured for now (only 8), so it wants/expects another drive to handle the
load.
Since you have no Group parallelism set , the parallelism setting of each
client in the group factors into the total concurrent sessions a group will
attempt to stream to your drives... I noticed when we upgraded once, all the
client parallelism changed from a default of 4 to like something like 12, and I
had to go and set them back to 4 or less (depending on the client, some are old
Alpha/VMS client that can't handle more than 1 or 2 concurrent sessions).
Or you could set the group parallelism to 8 or less (to match the current drive
settings of 4 times 2 drives) and see if that stops the additional volume
requests...
I bet that's exactly what's happening. I've seen it many times. The
drive parallelism is not an absolute high water mark. NW can and will
increase that if there are not enough available drives, and/or tapes, to
handle the save streams that are trying to send data.
The one thing that does control or limit this is the client parallelism
and possibly the group parallelism. Not sure about pool parallelism. And
obviously the server parallelism is the main starting point. I don't
think you can exceed that but can't recall how the number of snodes
plays into that.
Too bad they don't allow separate parallelism values for different
client resources for the same client. As soon as you change it for one
instance, it changes it for all of those.
George
-----Original Message-----
From: EMC NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On
Behalf Of Manel Rodero Blanquez
Sent: Friday, July 08, 2011 8:31 AM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: Re: [Networker] Waiting for 1 writable volume ...
Hi Goslin,
1 - Total Server parallelism is 16
2 - We have 2 LTO4 drives with target sessions = 4
3 - Group parallellism is 0
This version seems to have a little bit strange behaviour...
Any more ideas about what to check for?
Thanks.
El 07/07/2011 19:49, Goslin, Paul escribió:
It could be couple of things...
Look at
1. Total server parallelism setting (ours is set to 64 w 4 LTO-4 Drives, 8
target sessions per drive).
2. Target sessions per drive (the upgrade may have caused this # to be reduced,
so it thinks it needs more drives to accommodate the total concurrent sessions
it is attempting to run).
3. Parallelism setting of the running groups.... (do they add up to more than
#2 above ??)
-----Original Message-----
From: EMC NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On
Behalf Of Manel Rodero Blanquez
Sent: Thursday, July 07, 2011 9:22 AM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: [Networker] Waiting for 1 writable volume ...
Hello,
Recently, our server is asking always for 1 writable volume when it has
all 2 tapes drives with a tape inside and writing to them.
At the beginning of the backup it says "writing for 3 writable volumes"
and after mounting 2 tapes in the 2 drives, the message for 1 extra
volume is in the alert window.
Is this a new behaviour in the 7.6.1 versin? (we've recently upgraded
from 7.5.3 where we haven't seen this message during the backups, only
at the beginning while Legato mounts the tapes needed).
Thank you.
--
George Sinclair
Voice: (301) 713-3284 x210
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