ADSM-L

Re: [ADSM-L] Determining devclass FILE values (a.k.a. New Server - Part Deux)

2010-09-17 15:51:44
Subject: Re: [ADSM-L] Determining devclass FILE values (a.k.a. New Server - Part Deux)
From: Grigori Solonovitch <Grigori.Solonovitch AT AHLIUNITED DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Fri, 17 Sep 2010 22:49:15 +0300
>So, have you migrated to devclass FILE?
        I have migrated most of primary pools to devc/stgpool FILE and found 
them perfect (it was done as a preparation to use de-duplication in 6.x, by the 
way am still 5.5.4). It is good from any point of  view(backup, restore, making 
tape copies, etc). There is only one big disadvantage - cost of solution. By 
the way, with future de-duplication we are going to gain something in cost as 
well.

> For folks that are using devclass FILE, what values did you use for MAXCAP
> and/or MOUNTLimit?  How do you calculate/arrive at these numbers?
> Pro/con's for just letting the system determine MAXCAP?
     I was trying to find some information about calculating correct MAXCAP 
without any success. I think suitable MAXCAP is 32GB, 64GB, 128GB or 256 GB. I 
formated all primary pools with 64GB volumes and found no problems. Using 
bigger volumes can cause some problems. For example, it can limit number of 
mounts (parallel operations) - for volumes 256GB in 2TB storage pool number of 
mounts is limited to 8, because there is only 8 volumes in storage pool. I 
think values for MAXCAP and MOUNTLIMIT totally depend on size of storage pool 
and required number of parallel operations (backup and restores). KEEP IN MIND 
- MOUNTLIMIT is working only if there is enough volumes with status FILLING or 
EMPTY. FULL volumes can be mounted only for restore operations. Of course, 
problem can be resolved by creating required number of empty volumes, if there 
is no limit in storage pool size, but it is a dream of every admin.

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