Migrating from DPM

[john.aubrey]

Hello,
We are looking at migrating away from DPM. We are getting hit hard by REFS issues with tape backups. I was wondering if we could simply install Veeam on the same server as DPM. We could connect new SAS storage to dedicate to it. Stop all DPM backups, but keep for our retention period, then uninstall DPM off the box. In the mean time, Veeam takes over 100% of the backups then. Is this support or even a good idea? Other option is use an older server with storage until DPM is outside retention period, then migrate over Veeam to the "backup service server" we have.

[Gostev]

Hello! What ReFS issues are you experiencing, and what Windows OS version is that? I'm asking because ReFS issues may potentially impact the entire OS, so even having the dedicated storage may not help. Thanks!

[john.aubrey]

DPM 2016 and Windows Server 2016. Disk to tape backups are taking a long time. I did some disk i/o testes through windows and it didn't seem to show the significant disk queue that the tapes did, and the tapes were running really slow. Can Veeam still use NTFS for storage?

[john.aubrey]

REFS is only running on our SAS storage for backups. OS is still NTFS.

[ejenner]

I think the problem with DPM is that it takes control of the storage volume so it doesn't present with drive letters ect... It creates a logical volume for every file so you end up with loads of volumes (no drive letters) on the disk, like salami slices. Trying to share the same disk with Veeam which uses the whole volume with a drive letter in the normal way would conflict.

The idea of migrating Veeam is quite a good one as Veeam fully supports migration of the B&R server within the application. There is functionality dedicated to migrating the database ect. You can perfectly duplicate Veeam as it had been on the first server on a new server and it will continue to run as if nothing has changed, all the settings are retained.

The only issue it looks like you have is potentially not having any storage to send your Veeam backups to?

[john.aubrey]

We have another direct attached storage that will be available in ~30 days we could use. It's not as large as the current DPM one, but big enough for our current environment. Idea would be is use the extra only for Veeam, and then once everything is roll off of DPM's retnetion scheme, wipe and add to Veeam. There wouldn't be any overlap storage between the 2 programs.

[john.aubrey]

Hello! What ReFS issues are you experiencing, and what Windows OS version is that? I'm asking because ReFS issues may potentially impact the entire OS, so even having the dedicated storage may not help. Thanks!

From what I can pin down, our REFS storage 4k block size (DPM formatted it I believe), is getting really bad IO. We have very similar setup and results as this person.
https://social.technet.microsoft.com/Fo ... ial-write-

[Gostev]

Ah, make sense yes. We practically force customers to use 64KB clusters, which is 16 times more! And we had our lion share of issues with ReFS even with such volumes, so I feel really sorry for DPM... but, ReFS does get better (slow but steady).

[ejenner]

Anecdotally (i.e. no testing or evidence!) REfs seems ok writing data but the performance degrades a lot if you want to move files from one drive to another or performing delete operations. Reading seems slow as well.

For backup I don't think I'd use anything else as the space savings are impossible to argue with! I guess over time the improvements will continue. I'm looking forward to trying out the 2019 version.