I'd like to add one point regarding to the efficiency of volume-level
backup (butc or buta) or file-level backup with ADSM (TSM now). TSM
file-level backup is uses a "incremental forever" model. Only changed
files will be backed up every time (usually daily) and it does not require
a full backup routinely. For further speeding up the file-level
incremental backup, we have a script that examines the modification time of
each volume and skips volumes that are not modified since the last
incremental.
I agree with Brian that a combination of file-level backup and volume-level
backup would be better. The file-level incremental backup is good for
quick individual file recovery (that are not in the .backup volume anymore)
and the volume level is good for disk failure/disaster recovery.
Shyh-Wei Luan
"Brian T. Huntley" <[EMAIL PROTECTED]>@transarc.com on 10/03/2000 04:14:36
AM
Sent by: [EMAIL PROTECTED]
To: Paul Blackburn <[EMAIL PROTECTED]>
cc: [EMAIL PROTECTED]
Subject: Re: AFS backup/restore using ADSM
On Tue, 3 Oct 2000, Paul Blackburn wrote:
// One thing puzzles me: if I run an ADSM file backup
// (or any backup that traverses directories like tar)
// doesn't that mean that the entire filetree being
// backed up has to be accessed via the AFS cache?
//
// It doesn't seem very efficient compared with
// doing a regular AFS backup by volume.
// --
// cheers
// paul http://acm.org/~mpb
//
You are correct on both counts... everything does go through the cache,
and it's not as efficient as doing backup by volume (for more reasons
than just the cache). However, using a memory cache rather than a disk
cache reduces this. We have been doing back by vol and are currently
investigating going to a combination of back by vol and by file so that we
don't have to keep as much data around.
There are advantages and disadvantages to both methods; the trick is
finding the right choice for your site based on data retention, backup
window, and TSM(ADSM) server requirements.
-
Best regards,
Brian
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| Brian T. Huntley Systems and Network Engineer |
| Campus Information Services, Clarkson University |
| Ph/FAX: 315.268-6723/6570 |
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