[Veritas-bu] NBU Flashbackup vs Normal Backup

Discussion:

dy018

2008-07-02 08:02:14 UTC

Hi,

Recently i was told by symantec that using Flashbackup to backup the raw device will greatly increased the backup and restore time.

After reading through the admin guide abt the advanced client, i also understand that flashbackup also able to do file level restore instead on restoring the entire volume which i initially tot is going to be the trade off.

This spark a question, so a flashbackup is almost the same as a normal file level based backup which also able to retore individual files, wat are the cons of using flashbackup beside higher cost to buy the advanced client licenses? Anyone here knows the pros and cons?

Regards

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Justin Piszcz

2008-07-02 08:30:10 UTC

Permalink

Post by dy018
Hi,
Recently i was told by symantec that using Flashbackup to backup the raw device will greatly increased the backup and restore time.
After reading through the admin guide abt the advanced client, i also understand that flashbackup also able to do file level restore instead on restoring the entire volume which i initially tot is going to be the trade off.
This spark a question, so a flashbackup is almost the same as a normal file level based backup which also able to retore individual files, wat are the cons of using flashbackup beside higher cost to buy the advanced client licenses? Anyone here knows the pros and cons?
Regards

Pros: Backup 30-40 million files on Solaris in 8 hours.
Without it, it took 5-6 days.
Cons: Uses a lot of memory/CPU (possibly) to do so when you do not do a FULL
restore.

Justin.

Ed Wilts

2008-07-02 11:37:25 UTC

Permalink

Post by dy018
This spark a question, so a flashbackup is almost the same as a normal file
level based backup which also able to retore individual files, wat are the
cons of using flashbackup beside higher cost to buy the advanced client
licenses? Anyone here knows the pros and cons?

Not only is the Flash backup faster, we've found that it consumes
significantly less CPU than a "walk the file system" backup for file systems
with a lot of files.

The largest con is that it will back up the full size of the volume for a
full, whether the space is allocated or not. In other words, if you have
only 1 GB of data on a 1 TB volume, you'll still back up 1 TB.

You can not suspend Flashbackups - once they start, you must either finish
them or kill them off and start over. There is no checkpointing.

.../Ed

--
Ed Wilts, Mounds View, MN, USA
RHCE, BCFP, BCSD, SCSP, SCSE
mailto:***@ewilts.org

If I've helped you, please make a donation to my favorite charity at
http://firstgiving.com/edwilts

Ueli Schweizer

2008-07-02 11:56:19 UTC

Permalink

Data fragmented on disk will also be backed up fragmented using Flashbackup.
The restore of single files will be slower in this case, because the data
cannot be restored without various tape positioning.

Ueli Schweizer
CTO

AGITE Software AG · Boesch 43 · CH-6331 Huenenberg · Switzerland
Direct: +41 79 204 9190 · Phone: +41 41 781 5678 · Fax: +41 41 781 5677
***@AGITE-Software.com · http://www.AGITE-Software.com

backupVISUAL...
...we make life on backup easy

-----Original Message-----
From: veritas-bu-***@mailman.eng.auburn.edu
[mailto:veritas-bu-***@mailman.eng.auburn.edu] On Behalf Of dy018
Sent: Wednesday, July 02, 2008 5:02 AM
To: VERITAS-***@mailman.eng.auburn.edu
Subject: [Veritas-bu] NBU Flashbackup vs Normal Backup

Hi,

Recently i was told by symantec that using Flashbackup to backup the raw
device will greatly increased the backup and restore time.

After reading through the admin guide abt the advanced client, i also
understand that flashbackup also able to do file level restore instead on
restoring the entire volume which i initially tot is going to be the trade
off.

This spark a question, so a flashbackup is almost the same as a normal file
level based backup which also able to retore individual files, wat are the
cons of using flashbackup beside higher cost to buy the advanced client
licenses? Anyone here knows the pros and cons?

Regards

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dy018

2008-07-02 14:33:16 UTC

Permalink

Thanks everyone for your input.

BTW Ueli, can i ask you abt slow restore. You mention for single file restore require various tape positioning, meaning to restore 1 file, it need to position the tape afew time before restoring the entire file? whereas a normal filesystem backup when retore a single file only require 1 time postioning? So the multiple times taken for the positioning wil affect the overall restore timing?

Post by Ueli Schweizer
Data fragmented on disk will also be backed up fragmented using Flashbackup.
The restore of single files will be slower in this case, because the data
cannot be restored without various tape positioning.
Ueli Schweizer
CTO
AGITE Software AG · Boesch 43 · CH-6331 Huenenberg · Switzerland
Direct: +41 79 204 9190 · Phone: +41 41 781 5678 · Fax: +41 41 781 5677
Ueli.Schweizer < at > AGITE-Software.com · http://www.AGITE-Software.com
backupVISUAL...
...we make life on backup easy
-----Original Message-----
From: veritas-bu-bounces < at > mailman.eng.auburn.edu
[mailto:veritas-bu-bounces < at > mailman.eng.auburn.edu] On Behalf Of dy018
Sent: Wednesday, July 02, 2008 5:02 AM
To: VERITAS-BU < at > mailman.eng.auburn.edu
Subject: [Veritas-bu] NBU Flashbackup vs Normal Backup
Hi,
Recently i was told by symantec that using Flashbackup to backup the raw
device will greatly increased the backup and restore time.
After reading through the admin guide abt the advanced client, i also
understand that flashbackup also able to do file level restore instead on
restoring the entire volume which i initially tot is going to be the trade
off.
This spark a question, so a flashbackup is almost the same as a normal file
level based backup which also able to retore individual files, wat are the
cons of using flashbackup beside higher cost to buy the advanced client
licenses? Anyone here knows the pros and cons?
Regards
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Ueli Schweizer

2008-07-02 15:20:40 UTC

Permalink

Flashbackup backups data by reading block after block (physical order). If a
file is not stored in consecutive blocks on disk it will not be stored in
consecutive blocks on tape. If you restore such a file the data has to be
collected from different positions of a tape or, even worst, from different
positions on multiple tapes. That of course leads to slower file restores,
although NetBackup does a great optimization job on that.

This disadvantage is as bigger as more fragmented your data on disk is.

On the other hand, if you need to restore the whole disk it will be much
faster, because you read consecutive disk blocks from tape and there is
nearly no disk positioning necessary.

Ueli Schweizer
CTO

AGITE Software AG · Boesch 43 · CH-6331 Huenenberg · Switzerland
Direct: +41 79 204 9190 · Phone: +41 41 781 5678 · Fax: +41 41 781 5677
***@AGITE-Software.com · http://www.AGITE-Software.com

backupVISUAL...
...we make life on backup easy

-----Original Message-----
From: veritas-bu-***@mailman.eng.auburn.edu
[mailto:veritas-bu-***@mailman.eng.auburn.edu] On Behalf Of dy018
Sent: Wednesday, July 02, 2008 11:33 AM
To: VERITAS-***@mailman.eng.auburn.edu
Subject: [Veritas-bu] NBU Flashbackup vs Normal Backup

Thanks everyone for your input.

BTW Ueli, can i ask you abt slow restore. You mention for single file
restore require various tape positioning, meaning to restore 1 file, it need
to position the tape afew time before restoring the entire file? whereas a
normal filesystem backup when retore a single file only require 1 time
postioning? So the multiple times taken for the positioning wil affect the
overall restore timing?

Post by Ueli Schweizer
Data fragmented on disk will also be backed up fragmented using Flashbackup.
The restore of single files will be slower in this case, because the
data cannot be restored without various tape positioning.
Ueli Schweizer
CTO
AGITE Software AG 7 Boesch 43 7 CH-6331 Huenenberg 7 Switzerland
Direct: +41 79 204 9190 7 Phone: +41 41 781 5678 7 Fax: +41 41 781
5677 Ueli.Schweizer < at > AGITE-Software.com 7
http://www.AGITE-Software.com
backupVISUAL...
...we make life on backup easy
-----Original Message-----
From: veritas-bu-bounces < at > mailman.eng.auburn.edu
[mailto:veritas-bu-bounces < at > mailman.eng.auburn.edu] On Behalf Of dy018
Sent: Wednesday, July 02, 2008 5:02 AM
To: VERITAS-BU < at > mailman.eng.auburn.edu
Subject: [Veritas-bu] NBU Flashbackup vs Normal Backup
Hi,
Recently i was told by symantec that using Flashbackup to backup the
raw device will greatly increased the backup and restore time.
After reading through the admin guide abt the advanced client, i also
understand that flashbackup also able to do file level restore instead
on restoring the entire volume which i initially tot is going to be
the trade off.
This spark a question, so a flashbackup is almost the same as a normal
file level based backup which also able to retore individual files,
wat are the cons of using flashbackup beside higher cost to buy the
advanced client licenses? Anyone here knows the pros and cons?
Regards
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dy018

2008-07-02 15:39:38 UTC

Permalink

Thanks for the clarification Ueli, i got what you mean and also understand the trade off of having faster backup speed. :)

Post by Ueli Schweizer
Flashbackup backups data by reading block after block (physical order). If a
file is not stored in consecutive blocks on disk it will not be stored in
consecutive blocks on tape. If you restore such a file the data has to be
collected from different positions of a tape or, even worst, from different
positions on multiple tapes. That of course leads to slower file restores,
although NetBackup does a great optimization job on that.
This disadvantage is as bigger as more fragmented your data on disk is.
On the other hand, if you need to restore the whole disk it will be much
faster, because you read consecutive disk blocks from tape and there is
nearly no disk positioning necessary.
Ueli Schweizer
CTO
AGITE Software AG · Boesch 43 · CH-6331 Huenenberg · Switzerland
Direct: +41 79 204 9190 · Phone: +41 41 781 5678 · Fax: +41 41 781 5677
Ueli.Schweizer < at > AGITE-Software.com · http://www.AGITE-Software.com
backupVISUAL...
...we make life on backup easy
-----Original Message-----
From: veritas-bu-bounces < at > mailman.eng.auburn.edu
[mailto:veritas-bu-bounces < at > mailman.eng.auburn.edu] On Behalf Of dy018
Sent: Wednesday, July 02, 2008 11:33 AM
To: VERITAS-BU < at > mailman.eng.auburn.edu
Subject: [Veritas-bu] NBU Flashbackup vs Normal Backup
Thanks everyone for your input.
BTW Ueli, can i ask you abt slow restore. You mention for single file
restore require various tape positioning, meaning to restore 1 file, it need
to position the tape afew time before restoring the entire file? whereas a
normal filesystem backup when retore a single file only require 1 time
postioning? So the multiple times taken for the positioning wil affect the
overall restore timing?

Post by Ueli Schweizer
Data fragmented on disk will also be backed up fragmented using

Flashbackup.

Post by Ueli Schweizer
The restore of single files will be slower in this case, because the
data cannot be restored without various tape positioning.
Ueli Schweizer
CTO
AGITE Software AG 7 Boesch 43 7 CH-6331 Huenenberg 7 Switzerland
Direct: +41 79 204 9190 7 Phone: +41 41 781 5678 7 Fax: +41 41 781
5677 Ueli.Schweizer < at > AGITE-Software.com 7
http://www.AGITE-Software.com
backupVISUAL...
...we make life on backup easy
-----Original Message-----
From: veritas-bu-bounces < at > mailman.eng.auburn.edu
[mailto:veritas-bu-bounces < at > mailman.eng.auburn.edu] On Behalf Of
dy018
Sent: Wednesday, July 02, 2008 5:02 AM
To: VERITAS-BU < at > mailman.eng.auburn.edu
Subject: [Veritas-bu] NBU Flashbackup vs Normal Backup
Hi,
Recently i was told by symantec that using Flashbackup to backup the
raw device will greatly increased the backup and restore time.
After reading through the admin guide abt the advanced client, i also
understand that flashbackup also able to do file level restore instead
on restoring the entire volume which i initially tot is going to be
the trade off.
This spark a question, so a flashbackup is almost the same as a normal
file level based backup which also able to retore individual files,
wat are the cons of using flashbackup beside higher cost to buy the
advanced client licenses? Anyone here knows the pros and cons?
Regards
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_______________________________________________
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