Forever Forward - Merge time?

[AlainRussell]

I'm curious what merge time people are seeing with forever forward backups? I've noticed that a daily merge will take ~7-8 hours on our infrastructure - which was about the same time that a synthetic full would take once a week. What times are other people seeing?

We have VIBs of approximately 60-70GB a day (which also seems high so I'll look at that next in my quest to speed backups up a bit)

[dellock6]

Hi Alain,
seems high because previously if was smaller? Do you have any number to do a comparison? Because forever forward only have to merge a single vib file, while the synthetic full has to merge the entire weekly chain of incrementals, thus usually taking much more time.

With 70 GB of increment, you should expect 140 GB of I/O activity on your repository to do the merge. Say it's able to run at 20 MBs (random IO) it would take around 7000 seconds, which are almost 2 hours.

[AlainRussell]

Yes - numbers seem high to me - previously I'd have once a week 7-8 hours for synthetic full, now I have this daily for merge. Looking at SAN HQ (Equallogic SANs) I can see that over the merge time I'm getting about 120 read IOPs, 120 write IOPs (12MB/s).

Everything I can see is not working hard, low SAN load, low Veeam CPU, low network usage - but it still seems to take a long time. Interestingly - a GFS merge on my offsite backup takes just over 2 hours (lower grade hardware - Synology)

[dellock6]

How are you using the EqualLogic storage? Veeam using a vmdk? direct attached volume? Is there any other workload on that storage running while the merge is running too?

Nothing else has changed in the repository while upgrading to v8?

[AlainRussell]

Equallogic is direct attached, nothing else using it (dedicated for backups only), currently 2x 12 disk units with load balancing. We had some noticeable slowdowns with our V8 upgrade that we were working with support on - case #00679061.

This Veeam server is a rebuild and re-configure from scratch as support could not pinpoint any issues. So clean install, backups mapped and then backup method changed to forever forward.

[dellock6]

Ok, if support is involved better wait and see what they will find out. Keep us updated please.

[andreasaster]

Hi, Alain,

we are seeing the same problem. We have vibs with 500GB and the merge takes > 50h. So we are constrained to disable and reenable the job to do our daily backups. How is the call going on? Do you have a solution?

Regards,
Andreas

[foggy]

The OP's case is still under investigation, you can open your own case so that engineers have more information about the issue.

[Gostev]

The OP's case is still under investigation

To be precise, it was closed a few weeks ago due to no responses from the customer.