For file devclass, I generally don't worry about maximum volumes because I
don't set the volumes up as scratch, I predefine them.
Just something else that can cause issues for the customer, and reports of
other people seeing the coming and going of scratch file volumes causing
fragmentation in the filesystem. Better to define the volumes same as a random
DISK pool.
For mountlimit, it's just the maximum number of client processes you expect to
be writing to that drive at once. Or set to 999, no reason to restrict it.
For maxcapacity, it just has to be larger than the largest container volume you
plan to create in that pool.
If you have no plans for dedup, you have no REQUIREment for the file devclass.
And what I HATE about the file devclass, is that you don't get pool failover.
If the pool fills up before you can migrate out, your backups fail, rather than
waiting for a tape from the NEXTSTGPOOL.
If the data is going to migrate off to another pool, so the disk pool gets
emptied frequently anyway, what benefit to having a filepool?
And if it isn't emptied every day, you will have to run reclamation on it.
So when it's just a "buffer" diskpool, I prefer to use DISK rather than FILE.
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Zoltan Forray
Sent: Thursday, September 19, 2013 11:34 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] DISK vs FILE DevClass
We are in a transition of our SAN storage from one EMC box to another.
Since this requires my relocating 18TB of TSM server storage, I thought I
would take this opportunity to revisit FILE devclass vs DISK, which we are
using now.
I have been reading through the Linux Server Admin Guide on the "pro's and
con's" of both devclasses. Still not sure if it would be better to go with
FILE. Here is some info on what this server does,.
For the server that would be using this storage, the sole backups are Lotus
Notes/Domino servers, so the backup data profile is not your usual data mix
(largely Notes TDP).
No dedupe and no plans to dedupe.
No active storage and no need for it.
4-5TB daily with spikes to 15TB on weekends - 95%+ is TDP
When creating/updating the FILE devclass, how do I calculate/guesstimate the
values for MOUNTLIMIT and MAXIMUM CAPACITY as well as the MAXIMUM VOLUMES?
Unfortunately, the storage they assigned to me on the VNX5700 is broken up into
8-pieces/luns, varying from 2.2TB to 2.4TB, each.
Looking for some feedback on which way we should go and why one is preferable
than the other.
--
*Zoltan Forray*
TSM Software & Hardware Administrator
Virginia Commonwealth University
UCC/Office of Technology Services
zforray AT vcu DOT edu - 804-828-4807
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