Isn't that what I said? 

"- Disk staging also has "low water mark" that will stop de-staging once it 
hits that %."

Here's the verbiage from the 6.0 manual:

Once the High Water Mark is reached, space is created on the disk storage unit 
until the Low Water Mark is met. To do this, NetBackup may copy images to other 
storage units or expire images (oldest first) to free space. The Low Water Mark 
setting cannot be greater than the High Water Mark setting.


---
W. Curtis Preston
Backup Blog @ www.backupcentral.com
VP Data Protection, GlassHouse Technologies 
-----Original Message-----
From: Martin, Jonathan [mailto:JMARTI05 AT intersil DOT com] 
Sent: Thursday, August 02, 2007 11:32 AM
To: Curtis Preston; Paul Keating; Dyck, Jonathan; VERITAS-BU AT 
mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] Question on Disk-as-Disk Targets NBU 5.1 MP5

Clarification on "Low Water Mark" - NBU 6.0 Won't stop destaging (writing 
images to tape) until it gets to the low water mark, a full DSU will stop 
expiring images on disk that are already on tape once it gets to X% full.

No?

-Jonathan

-----Original Message-----
From: Curtis Preston [mailto:cpreston AT glasshouse DOT com] 
Sent: Thursday, August 02, 2007 2:22 PM
To: Martin, Jonathan; Paul Keating; Dyck, Jonathan; VERITAS-BU AT 
mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] Question on Disk-as-Disk Targets NBU 5.1 MP5

I just reviewed the release notes for 5.0, 5.1, & 6.0, and here's my summary of 
the disk features in the last several versions.

4.5 and below:

- basic disk storage units, no disk staging, etc.

==================================
5.0 introduced disk staging 

- (Disk staging storage unit, or DSSU), but it only de-stages one backup at a 
time (slow)

- DSUs/DSSUs have no concept of capacity.  NBU would keep sending backups to a 
DSU even if a filesystem was full; they will just fail over and over.

==================================
5.1 minor improvements in disk area

- introduced unspecified performance improvements for disk backups

- DSUs/DSSUs have no concept of capacity.  NBU would keep sending backups to a 
DSU even if a filesystem was full; they will just fail over and over.

==================================
6.0 Major improvements in disk backups

- Summary is that if you want to do lots of disk stuff you should upgrade to 
6.0.  HUGE improvements in this area.

- Introduced capacity concept.  It monitors the space available on the DSU 
(i.e. like using df on unix or looking at disk properties in Windows), and you 
can specify a "high water mark" that tells it to stop sending data to the DSU 
when it reaches n% full


- Backups that are in process will fail when they hit the high water mark.  If 
you have checkpoints enabled, they'll restart where they left off on the next 
DSU (if using storage unit groups).

- New backups will not be assigned to a full DSU

- Disk staging is now just a property of a DSU (no more DSSUs)

- Disk staging now de-stages multiple backups at a time

- Disk staging also has "low water mark" that will stop de-staging once it hits 
that %.


---
W. Curtis Preston
Backup Blog @ www.backupcentral.com
VP Data Protection, GlassHouse Technologies 

-----Original Message-----
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu 
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Martin, 
Jonathan
Sent: Thursday, August 02, 2007 10:25 AM
To: Paul Keating; Dyck, Jonathan; VERITAS-BU AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] Question on Disk-as-Disk Targets NBU 5.1 MP5

To clarify,  you can group DSUs and DSSUs in 6.0 but if the disk fills up any 
backups writing to it fail.  One of the 6.5 features is that when the DSU or 
DSSU fills up the backups will move on to a storage unit with space.  I'm not 
100% sure exactly how this works, only read the product docs on 6.5.  I look 
forward to implementing it later this year however.

-Jonathan

-----Original Message-----
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu 
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Paul 
Keating
Sent: Thursday, August 02, 2007 12:56 PM
To: Dyck, Jonathan; VERITAS-BU AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] Question on Disk-as-Disk Targets NBU 5.1 MP5

Ya can't do it with NBU 5.x (group DSSUs in a SUG) It's a "new fauture" in 6.x

Paul
-- 


> -----Original Message-----
> From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
> [mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Dyck, 
> Jonathan
> Sent: August 2, 2007 12:51 PM
> To: VERITAS-BU AT mailman.eng.auburn DOT edu
> Subject: [Veritas-bu] Question on Disk-as-Disk Targets NBU 5.1 MP5
> 

> Can I infer that there may be an issue with grouping disk-as-disk 
> filesystems in a storage unit grouping with Netbackup 5.1?
> That'd be a
> huge concern of mine...  Is anyone (other poor souls like me who can't 
> afford a VTL) out there grouping disk-as-disk filesystems for primary 
> backup?
====================================================================================

La version française suit le texte anglais.

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