I think it does though it doesn't seem to affect anything.
Our nodes are all set to MaxNumMP of 1. Our FILE DIRMC pool is set for a
mount limit of 12.
When a node is backing up to the system, the DIRMC volume is mounted and
remounted repeatedly, but each mount occurs in less than a second, and the
only impact that I've seen is more "volume mounted" messages in the
ActLog.
I limited MaxNumMP because each of our tape libraries has four drives.
When backups occur during maintenance processes - mainly reclamation -
those processes can tie up as many as three drives, so all incoming data
is funneled to one drive.
History...
When I was running direct-to-tape on our LTO library, the library would
round-robin tapes through the one available drive and each tape would
receive one batch of incoming data from one node. The practical result
was that backups took forever and the library sort of beat itself to
death. Limiting MaxNumMP was an attempt to reduce the round-robin'ing. It
didn't work. Increasing that limit *might* have worked, but we didn't try
it.
Instead I implemented a small upstream disk pool with a 25 MB MaxSize.
That gives the nodes someplace to land data when "their" tape is not
available, and reduces the round-robin'ing and MediaWait time on the
system. It also allows me to leave "last night's" data on disk, if
smaller than 25 MB, for immediate access during restores. That's the
first time we've used that "best practice" since we installed ADSM 2 six
years ago.
Tab Trepagnier
TSM Administrator
Laitram Corporation
Richard Foster <[EMAIL PROTECTED]>
Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]>
12/18/2002 09:14 AM
Please respond to "ADSM: Dist Stor Manager"
To: [EMAIL PROTECTED]
cc:
Subject: Re: MAXNUMMP question
> I have a question regarding the node parameter MAXNUMMP. Does this
> affect only tape mounts or does it affect sequential file mounts also?
A good question. I don't know the answer, but those people who run the
FILE-based DIRMC setup might know, as they're using this type of pool. Tab
and the others: have you had to increase this value?
Richard Foster
Norsk Hydro
