The size of the journal(s) db(s) (there is no log ...) depends on the
volume of change activity on the file system(s) being
journaled.
Keep in mind that there is one journal db per file system being journaled.
Journal Based Backup really works best for file systems with a small to
moderate (15% objects change between backups)
volume of change activity.
The journal db will continue to grow on disk as does the number of change
notifications from the file system.
Journal db entries are removed from the journal after the entry is
processed (the object is backup or expired via Jbb)
and the space will be reused, but the size on disk of the journal never
shrinks (unless of course the journal is invalidated and deleted).
For example, if 10,000 objects change the journal db will physically
allocate disk space for 10,000 journal entries (there is always only
one entry per object, multiple notifications for the same object are
reflected in the same journal entry).
Once Journal Based Backup is performed the 10,000 journal entries will be
processed and the space within the journal db
will be marked for reuse, and provided no more than 10,000 objects change
no additional disk space will be allocated.
If subsequently 15,000 objects change disk space will be allocated for an
additional 5,000 entries.
As for precise disk space usage, the answer depends really depends on the
depth of the file system directory
structure and the average name and path length of objects stored in the
journal (obviously it depends on which
objects change and generate journal entries).
The default value of the JournalDbSize configuration setting is 0, meaning
that size of the journal is only limited by the size of the
file system, and unless there is a compelling reason to limit the size it
is probably best to use the default.
Hope this helps .....
Pete Tanenhaus
Tivoli Storage Solutions Software Development
email: tanenhau AT us.ibm DOT com
tieline: 320.8778, external: 607.754.4213
"Those who refuse to challenge authority are condemned to conform to it"
---------------------- Forwarded by Pete Tanenhaus/San Jose/IBM on
10/30/2002 12:37 PM ---------------------------
prasanna S ghanekar <gpresy AT lycos DOT com>@VM.MARIST.EDU> on 10/30/2002
11:38:01 AM
Please respond to gpresy AT lycos DOT com
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
cc:
Subject: Re: Journaling
Hello everyone,
Sorry for stepping in the middle !
WHen you start Journaling service, what should be the consideration for
that database/log size on a NTFS partition.
Thanks
Prasanna Ghanekar
--
On Tue, 29 Oct 2002 10:25:26
Pete Tanenhaus wrote:
>Just to clarify, Journal Based Backup only backs up objects which have
>changed based on solely on the
>contents of the change journal maintained by the journal service.
>
>The change journal is maintained based on change notifications reported by
>the filesystem.
>
>Traditional incremental backup must build the entire list of objects for
>the local file system
>and the entire list of objects stored on the server file space for that
>file system and compare
>the two lists to derive a list of backup candidates.
>
>Note that the above is done regardless of how many objects are actually
>backed up, if only one object
>changes both lists must still be built and processed.
>
>
>Pete Tanenhaus
>Tivoli Storage Solutions Software Development
>email: tanenhau AT us.ibm DOT com
>tieline: 320.8778, external: 607.754.4213
>
>"Those who refuse to challenge authority are condemned to conform to it"
>
>---------------------- Forwarded by Pete Tanenhaus/San Jose/IBM on
>10/29/2002 10:18 AM ---------------------------
>
>Andrew Raibeck/Tucson/IBM@IBMUS AT VM.MARIST DOT EDU> on 10/29/2002 09:36:12 AM
>
>Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
>
>Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
>
>
>To: ADSM-L AT VM.MARIST DOT EDU
>cc:
>Subject: Re: Journaling
>
>
>
>Turning on journaling does not require backing up all files (unless they
>have all changed).
>
>Regards,
>
>Andy
>
>Andy Raibeck
>IBM Software Group
>Tivoli Storage Manager Client Development
>Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS
>Internet e-mail: storman AT us.eyebm DOT com (change eye to i to reply)
>
>The only dumb question is the one that goes unasked.
>The command line is your friend.
>"Good enough" is the enemy of excellence.
>
>
>
>
>"Gill, Geoffrey L." <GEOFFREY.L.GILL AT SAIC DOT COM>
>Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
>10/29/2002 07:23
>Please respond to "ADSM: Dist Stor Manager"
>
>
> To: ADSM-L AT VM.MARIST DOT EDU
> cc:
> Subject: Journaling
>
>
>
>Why, after turning on Journaling, is TSM now going to back up the whole
>600GB "AGAIN"!
>
>Geoff Gill
>TSM Administrator
>NT Systems Support Engineer
>SAIC
>E-Mail: <mailto:gillg AT saic DOT com> gillg AT saic DOT com
>Phone: (858) 826-4062
> Pager: (877) 905-7154
>
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