Can we estimate the ETA of a restore job?

[Kisad]

Hi All,

Is there any way to find out the estimated time that a netbackup restore will take to complete.I keep getting asked this question very often,specially during Disaster Recovery.I know a restore depends of lot of factors but the all the customer wants is an eta which i'm uanble to provide accurately.Appreciate any help in this regard.Thanks

[NathanNieman]

I have always found it hard to figure out how log it will take to restore a file.

[mph999 · Accepted solution]

My standard answer, which over the years has proven to be fairly accurate is '

Anywhere beteeen x2 and x3 times the time it took to backup ...

Sometimes it does, other times it finishes quicker, so the end user, is happy.

Martin

PS.  Pray they haven't run the backup with a stupidly high MPX value of 20 or something - this throws my theory out of the window ...  

[Nicolai]

The amount files does also influence restore time. Not log time ago a server used 12 hours to restore 300.000 12K files. But the restore request contained 1.2 million files.

My rule of thump is the same as Martin - 2 to 3 times backup time.

[mph999]

Yippeee, it's always good with Nicolai and I give the same answer ....

Just need Marianne to come along now ...

[Omar_Villa]

What i know is while MPX reduces backups times it increase restore by the same factor, so a 4x MPX backup will take 4x times of what it took to backup.

[Marianne]

I have seen so many different restore speeds over the years that the line in the subject is my only answer.

I have seen extremely bad restore performance back in 100BaseT days with client NICs configured as AutoNegotiate.
I have also seen restore speed from MPX=8 backup that ran faster than the backup! Not a once-off either - this customer was running Informix backups on a daily basis at Production and restoring next day at DR. Good restore performance was consistent.

Other that my subject line, I agree - rather prepare user for 2-3 times slower than backup. Anything faster = happy customer!

[mph999]

Agree with Marianne, I sometimes give the answer, ask me again when it has finished ...

[Anonymous]

It also depends where the backup image for the specific restore is located....so factor in

restore from tape or disk...disk you would expect to be faster.

[Kisad]

Thank You Everyone for responding with you views and opinions.

My standard answer too has been 2-3 times the time a backup has taken.Ofcourse with the usual disclaimeer that  several factors like network,multiplex setting extra wil also influence the time. But unfortunately the customer isnt happy with this answer and obviously i havent been able to give an exact ETA.

I guess we will leave it at that till the time we find some other option,maybe in future releases.

One last question,whose post should i mark as solution?

[Mark_Solutions]

You should mark the answer that you feel gives you most of what you are looking for

[mph999]

"I guess we will leave it at that till the time we find some other option,maybe in future releases."

You will never get this - it is impossible to say until it has completed.

Martin