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Empty Staging Area

MickBoosh
Level 5

Hi,

I noticed our 13Tb staging area was empty today, usually it has about 7 days of backups in there. I thought this was strange so I did a small backup which was successful. When the DSSU job ran 30 minutes later it moved it to tape.

We have two staging areas, and a master and media server. The older, smaller staging area is fine.

I haven't changed anyting recently!

Can anyone explain why things are going to tape so quickly?

Mike

Netbackup 6.5.5

19 REPLIES 19

Android
Level 6
Partner Accredited Certified
I would select your DSSU's from the "Storage Units" portion of the admin console.  When the "Change Storage Unit" window appears, select the staging schedule button.   In the new window that appears, check the Frequency in the "Schedule Type" section and also look at the "Start Window".  Look for anything that could explain why the DSSU is moving the images to tape so quickly.

Maybe something here was changed unintentionally? 

MickBoosh
Level 5

Yes I've looked there,both our storage units are set to 1 hour but I was under the impression that it would only go to tape when the the disk reached the high watermark level? (98%)

So if both are set to 1 hour why is one storage area getting "cleared" and the other one isn't?


Android
Level 6
Partner Accredited Certified

The high water mark does not determine when an image will go to tape.  On a Basic Disk Storage Unit or DSSU, images will be copied to tape depending on the configuration within the staging configuration area for that DSSU. However, the images will remain on disk as well, so that they can be restored more quickly in the event that they are needed.  They will only be removed from disk when the image expires, or, when the high water mark is reached.

When the high water mark is reached, NBU will look at images on the DSSU and remove those that have already been duplicated to tape, that have the oldest time stamp (remove older images fisrt) until it gets to the low water mark (80% by default).

As to why the images are being removed from one DSSU immediately and not the other, it must have to do with the way your NBU environment is configured.  Maybe the one has images from a Strorage Life Cycle Policy that are configured to remove the primary copy as soon as it is duplicated to tape.

Look at the configuration differences betweent he DSSU's and the policies that use them as their storage devices.  I'm sure you'll find there is a difference in the confi that is causing this behavior.






MickBoosh
Level 5

The DSSU's are identical as far as I can see. The policies look ok as well.


Android
Level 6
Partner Accredited Certified

Two staging methods
NetBackup offers two methods to stage backups:

Basic disk staging Basic disk staging consists of two stages. First, data is stored on the initial storage unit (disk staging storage unit). Then, per a configurable relocation schedule, data is copied to the final location. Having the images on the final destination storage unit allows the space to be freed on the disk staging storage unit when it is needed. For more information, see “Basic disk staging” on page 244. The following storage unit types are available for basic disk staging: BasicDisk, NearStore, and tape.

Staging using Storage Lifecycle Policies Staged backups that are configured within the Storage Lifecycle Policies utility also consist of two stages: Data on the staging storage unit is copied to a final destination, however, the data is not copied per a specific schedule. Instead, the administrator can configure the data to remain on the storage unit until either a fixed rention period is met, or until the disk needs additional space, or until the data is duplicated to the final location. No BasicDisk, SnapVault, or disk staging storage units can be used as destinations in a lifecycle. For more information, see “Storage Lifecycle Policies” on page 253.
The staging method that is used is determined in the policy Attributes tab. The Policy storage selection determines whether the backup goes to a storage unit or a lifecycle.


So with the above information I would select "Storage Units" from the menu tree on the left int he Admin Console and look at the list produced inthe right hand pane to see what the value is for "Disk Type". 


MickBoosh
Level 5

Yeah it's Basic Disk for both of them.

Christoph_Linde
Level 5
Employee
What is your low water mark setting?

And is there anything else on the same volume?

Tell us the setting for low water mark and the actual space utilization of the disk.

MickBoosh
Level 5

Christoph, the low watermark is 85%, high 98% (same on both our staging areas)

There's nothing else on the volume. Not sure what you mean about space utilization?

MickBoosh
Level 5

Anyone?

marekkedzierski
Level 6
Partner
Maybe someone expired images from disk storage unit ?
Search your NB catalog for images stored on Disk. If catalog list your images - maybe someone formatted your disk.. if not - images are removed by NB.

MickBoosh
Level 5

No one expired images, It's only me who uses it really. Also, this is on going, i can see images on there in the morning and they disappear to tape shortly after.

I've logged a call with symantec but they haven't got back to me yet.....

netengineerguy
Not applicable
Has anyone found a fix to this? I just started experiencing this on one of my servers and the others are fine, just like MickBoosh.

Christoph_Linde
Level 5
Employee
Okay, again

it is normal, that images get copied to tape as soon as the duplication schedule runs. That is working as designed. They then stay on the disk as long as the high water mark is not reached.

If the high water mark is reached, the images already staged will be deleted beginning with the oldest image to the low water mark.

I had one example in the past where it did not work. That was if you have a Windows Media Server and use mount points for the DSU Path, than the following can happen:

Assume Drive D:\ has only 2 GB of size and you mount a volume to D:\DSU. If you then configure D:\DSU as path, the storage server will check D:\ for the space utilization of the storage unit and not the Volume mounted on D:\DSU.

So this will not work.

You can find out the actual utilization (disk space usage) from the perspective of DSU in the DSU itself. Click on properties and you will see the space free etc. Perhaps you will find out, that your DSU thinks you are allways more utilized then 85% which will lead to a removal of all images directly after they are staged to tape.

thesanman
Level 6
I've got the same issue!  It happened once; one of my media servers starting cleaning up images post the DSSU schedule running.  I logged a call with Symantec and setup logging but the stop/start of the NBU Master Server services caused the issue to go away.

Then a week later another media server started doing the same thing; fixed by a stop/start of NBU Media Server services.  Now another is doing it!

I had a call open with but closed it after the first one; I think it's time to open another.

I'm running NBu v6.5.5 across the board on Linux RHEL.

DeeEtta_Thomas
Not applicable
I have the same issue on one of my servers.  Checked all the suspect places and cannot figure out why images are being automatically deleted after they are written to tape, any answers from support?

thesanman
Level 6

No answers for me; I needed to enable full logging but when I did that and bounced NBU Master Server the problem went away.  Since then no issues seen.

There are some DSSU fixes for a similar issue in v6.5.6 which has just been released and was advised to consider that as a "fix" path.  Sugest if you are seeing the issue; try and enable full logging and get the logs to Symantec.

_5
Level 3
Partner
Hello folks,

I got a DSU's in the following manner 

E:\DSU1   ( backup size in DSU appox 300G)
E:\DSU2   ( backup size  in this DSU appox 600G) 

total E: drive is 1TB

both DSU used for staging purpose of diffrent polices.

my query is while taking a backup to DSU1 - reaches the high water mark  since both the DSU's reside on the same drive my DSU2 also will reaching the high water level mark at this point on the same time , Will the netbackup automatically remove the from images ( which is already copied to tape ) the both DSU's ? or only from the DSU1 ?

Regards
Vimal


Sacha_Brown
Level 5
Partner Accredited

Hi,

 

I am in the process of performing an upgrade from NBU 6.5 to 7.01 to different hardware. My question is whether the staging disk should be configured on Master server or media server. My guess is media server.

 

Any help would be appreciated..

 

Thanks

Marianne
Moderator
Moderator
Partner    VIP    Accredited Certified

Khamatee, please start a new discussion.

Your query is not really related to this thread.