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Duplicate to tape slow comparing to direct backup to tape

Mrenbe
Level 3

Dear All,

I am a facing a speed issue when I duplicate a deduplicated backup from NAS to tape.

When I backup VM of my Hyper-V cluster directly on tape my job rate is between 3000MB/min and 3500MB/min. When I dedup from the Hyper-V Cluster on my NAS the job rate is around 1065 MB/min. Now I am duplicating my deduplicated backup from NAS to tape and the job rate is less than 1000MB/min. How could I increase the speed?

The connection between my backupexec server and my NAS is done through 2x 1Gbps (MCS policy Round Robin) with Jumbo frame. Do I need to disable "cheksum" or "large send" offloads or VMQ on the backup exec sever NICS?

Thanks in advance for your help

Michael

7 REPLIES 7

CraigV
Moderator
Moderator
Partner    VIP    Accredited

Hi,

 

Not sure this is going to be possible technically speaking.

Reason for this is that when data is backed up to a dedupe folder, all redundant information is removed leaving pointers, hence backups will become smaller and faster.

When duplicating to tape, this data is rehydrated to the original size. So backing up 1TB to  a dedupe folder might see you with a 400GB dedupe folder for instance. Duplicating to tape means it rehydrates to 1TB which will take processor time.

Thanks!

Mrenbe
Level 3

Craig,

Reason for this is that when data is backed up to a dedupe folder, all redundant information is removed leaving pointers, hence backups will become smaller and faster.

Let me just have a doubt for "Faster":

3,5To of VM backed up every days in incremental and 1 full per week. The full takes 1day and 20 hours and the incremental takes 23h46. Do you think that is in the average? Do you think it fast?

Thanks for your opinion.

 

Michae

lmosla
Level 6

exclude the Deduplication Storage Folder from any antivirus software also try running the verify portion of the jobs at a seperate time.

Mrenbe
Level 3

Of course I forgot to mention that I already excluded the Deduplication Storage Folder from any antivirus software.

If I copy a 4GB files to the Deduplication Stroage Folder (using copy-paste) the throughput rate is  280 MB/sec.

My current duplication job of a deduplicated backup has a througput of 761MB/min. then 12MB/sec. I have a deduplication backup job to deduplicated storage folder in parallel with a througput of 100MB/min either 1,6MB/sec.

Very poor performance.

In addition I have opened a ticket nea the support and they told me that the Deduplication Storage Folder is fragmented and that I need to defrag. An analyze shows them that my Deduplication Storage Folder is 0% fragmented.

CraigV
Moderator
Moderator
Partner    VIP    Accredited

...if you duplicate to anything other than another dedupe folder, it's going to rehydrate the data to the original size which is going to slow things down.

If you're duplicating to another medium AND running a backup to the dedupe folder in parallel then I'd say that's your issue. Run the dedupe backup first, let it complete and Verify, and THEN run the duplicate job and see what the performance is.

Copying data to a dedupe folder outside of BE isn't going to show you anything...that folder is managed by BE and copyuing data to it is going to lead to data of the original size which isn't deduped by the OS at all. You won't accomplish anything like this.

Thanks!

Artegic
Level 6

Mrenbe, in my experience, your performance numbers are absolutely normal. Writing to Backup Exec 2012 deduplication disk storage is notoriously slow, and reading from it (whether restoring or duplicating to tape) is even worse. What's more, the numbers are quite unpredictable. The same job may, for no apparent reason, vary in speed by a factor of 2 from one day to the next. Attempts to analyze or improve this proved futile. It's just the way this thing works.

Symantec promises that deduplication performance is much improved in Backup Exec 2014. I'm really looking forward to that version and I do hope the problem with deleting expired backup sets from disk, which is blocking the upgrade for us, will be solved soon.

Mrenbe
Level 3

No I mean I copied on the same Deduplication storage drive but not into the Deduplication Storage Folder itslef used by BE (I am not crazy). Just to explain that the performance to my network drive are right but Backup Exec is simply worst than slow.