Multiplexing / Multistreaming ideas

[colltech_1]

Master & two media servers running Windows 2003 & Netbackup 7.0.1

i80 tape library with 4 LTO5 drives

139 active backup clients mix of Windows 2000, 2003, 2008, Linux, Solaris, and 25 TB NDMP

The customer is adding more hosts to the backup schedule which is starting to slow things down a bit. I will have to start multiplex / multistream jobs in order to complete backups in the windows I have been given. I have seen where you can over multiplex / multistream and actually hurt performance.

I have standardized retention to diff's 3 weeks, fulls 3 months and monthly fulls 1 year on all jobs. Based on the current setup what would be a middle ground to use on multiplex / multistream? 

[mph999]

Not sure this will work.

Mutliplexing will 'mix' multiple streams, but this will only produce an speed improvement if each stream multiplexed would, on its own run slower than the speed of the drive.

Put another way if I have two streams that run at 80 MB/s each and take 1 hour each to backup, if I multiplex them together they won;t go any quicker,it will still take two hours.

Multistreaming to multiple drives however, may help.

The big issue with multiplexing is restores, mpx restores can take considerably longer.

A mpx value of 4 seems to be a good balance between backup performance and (taking into the details above) and restore speed.

Probably safe to say with the mpx value, you do not want to be in double figures.

I have seen big mpx values cause restores take 30+ hours, when the same data later backed up non mpx, took around 6 hours to restore.

Martin

[Marianne]

Firstly - examine your media servers' ability to stream LTO5 tape drives.
32- or 64-bit?
Memory?
CPU?

Old but still valid White Paper: https://www-secure.symantec.com/connect/sites/default/files/b-whitepaper_nbu_architecture_overview_1...

http://www.symantec.com/docs/HOWTO56210

I agree with Martin - MPX value of 4 (in STU as well as schedules) gives good backup and restore performance.

[Nicolai]

Very good post from both Martin & Marianne.

Try to calgulate or monitor the writing speed on the LTO5.

If writing speed on each of the LTO5 is lower than 160MB/sec multiplexing may speedup the totalt backup volume each night.  

But that said you absolout need 10GB ethernet on both media servers. If you don't have, then multiplexing won't help at all because the network would already be at it's max capacity.

[Mark_Solutions]

Excellent posts by everyone (as always!) so just to add to the mix ...

If the number of clients is going up then, as advised, do you calculations to see what is actually possible.

You may need to add in an extra Media Server to make the backups possible within the desired window .. or you may need 10g networks.

It may also be time, rather than having to spend more money on a larger tape library, more drives or extra media servers to add disk into you back system

There are some very high performance SATA disk arrays out there are very good prices and the difference they can make to you backups is surprising (as long as your media servers and network are capable)

The benefit is also that there are fewer limits on the number of jobs that can be run and when duplicated from disk to tape none of your backups are multiplexed so restores from tape are good.

Hope this helps

[colltech_1]

Master 

Xeon @ 266GHZ

31.9GB RAM

Windows 2003 Enterprise 32bit

Media Server 1

Xeon @ 266GHZ 

15.9GB Ram

Windows 2003 Enterprise 32bit

I might be able get the client to throw another media server in and MAYBE get 1 more drive but after that it is the typical make due with what they have. 

Media server 2 is actually behind a firewall which services the hosts on that side which is not really taxed.

I think it handles around 30 clients and all of the Exchange backups.

Media Server 2

Xeon @ 266GHZ 

15.9GB Ram

I think it handles around 30 clients and all of the Exchange backups.

The backups are running and completing OK but the weekend full's are starting to bleed into the later hours of Monday.

With a bit more tuning I can clean that up some but need to try and poke a big enough hole here and there to get the NDMP backups to run and not destroy everything else when they run. I have broken them up as much as I could to reduce long NDMP tape times but have a few volumes that are large that can not be broken up. 

This is just a sanity check

[Mark_Solutions]

Sounding like disk may really help out here, especially if tape time is causing you issues

One customer i dealt with had similar issue to yourself - backup always running until 10 am in the morning which also caused them issue when their tape collection arrived and backups were still in progress

The first night i added in disk all of their backups and the duplications to tape had completed by 7am - so four hours less and duplicated as well - makes a huge difference if you set it up right

[colltech_1]

What I did was 

set all jobs to multistream and multiplex of 4 on all jobs except for exchange. 

seems to be working out and jobs are finishing. have some bleed over from the weekend into monday but customer is not complaining 

I do not see where to mark this thread as solved.