I have found on some large disk pools, that is say, 5x the size of a tape,
we set migration to continue to yes, set the high level to 20, and low
to something like 3 to 5 percent. Yes, I do daily 'flush' the pools by
setting them to hi=0, lo=0 for a while before I do a db backup.
Why 20% for high? If the pool gets that much migratable data, it can fill
a tape. This way as a tape of data is ready to be migrated, it can pretty
much stream from disk to tape without waiting for additional data.
I have thought of making it 10% or half a tape worth, but I don't know if
I will gain much from it other than spinning tapes a little more often.
Oh yes, in the mornings, I do build my copypool tapes from disk data first,
before backing up my on-site tape pool.
-----Original Message-----
From: Mr. Lindsay Morris [mailto:lmorris AT SERVERGRAPH DOT COM]
Sent: Monday, June 23, 2003 8:45 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: How to query if there is data to migrate for a primary
storage pool??
I think most people use server scripts (or the older way, admin schedules)
to set migration up and down daily. Why are you using shell scripts?
Typically you'll write a server script that does most of the daily
housekeeping jobs, one after the other, and one admin schedule to fire it up
at 6 AM.
And in more direct answer: I don't think you need to care about whether
there is data to be migrated or not. Just set the himigration point down
(not quite to zero) once a day to kick off migration, then set it back up
(not quite to 100%) to discourage migration at might.
-----------------------------
Mr. Lindsay Morris
Lead Architect
www.servergraph.com
512-482-6138 ext 105
> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]On Behalf Of
> Lawrence Clark
> Sent: Monday, June 23, 2003 8:55 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: How to query if there is data to migrate for a primary
> storage pool??
>
>
> Not sure what your asking, but
>
> Select * from stgpools
>
> will give you stgpool data in total.
>
> >>> steve_taylor AT SYMPATICO DOT CA 06/21/03 05:28PM >>>
> Hi,
>
> Is there a SQL query example, that shows how we can determine if a
> storagepool has qualifying data that can migrate ....
>
> We have a shell script the lowers the thresholds (higmig=1, and
> lowmig=0) to force a migration..... and waits... eventually timing out,
> or finding a completion message...
>
> I was hoping there was a way to determine if we should even try to do a
> migration, to save lots of looping and sleeps in our shell scripts..
>
> Any suggestions would be appreciated..
>
> Thanks,
>
> Steve Taylor
>
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