type of incremental backup

[sentmemail]

should i run a culmulative incremental backup daily or should i run a differential incremental backup daily?
any advice?

thanks

 

[jjjon]

Depends on your Restore needs. If you need to restore a complete volume, with Cumulative Differential, you'd only need to retsore the last full, and the most recent Cum. Diff. tape. If on the other hand you use Incremental, you'd need to restore the last full, and every tape since to get your volume back up to date!

Personally, I'd go with Cum. Diff., it's easier to keep track of what tapes are required for a restore.

Jon

 

[sentmemail]

but there's no Cumulative Differential ??
there is only "culmulative incremental" or "differential incremental" to choose from...

 

[jjjon]

Sorry, what I meant to say was:-

Depends on your Restore needs. If you need to restore a complete volume, with Cumulative Incremental, you'd only need to restore the last full, and the most recent Cum. Diff. tape. If on the other hand you use Differential Incremental, you'd need to restore the last full, and every tape since to get your volume back up to date!

Personally, I'd go with Cum. Incr., it's easier to keep track of what tapes are required for a restore.

Jon

 

[sentmemail]

thanks!

i noticed that the backup images spans from 1 tape to another and i end up using 4 tapes per backup session. Which is 160GB of tape capacity and i know that my data is only 50GB!
Is there anyway to force netbackup to write the images to a tape until it is full then continue to another??

 

[PGPhantom]

As per a previous post ...

Streaming is the issue - If you enable streaming - What will happen in a 3 drive system is that c will be backed up by drive1, d by drive2, e by drive3 and if one exceeds capacity then a 4th tape will be used.

Just disable streaming and see what happens.

 

[sentmemail]

i need to enable streaming because i need the backup to compelete by next morning to be sent offsite.
if streaming is disabled the backup will run till noon.
any help?

 

[F4br1c3]

So if you don't want to use more than one tape by backup, you must disable multiplexing (and not multistreaming, difference is stream: flux come from computer, plexing: flux go to one tape)
If you don't : the only choice is to done duplicate.

That's your choice.

Hth

F@b

 

[sentmemail]

thanks guys!
i will give it a try

 

[sentmemail]

i have checked that media multiplexing is set to "1"
it should be disabled, am i right?

 

[F4br1c3]

So you want to put all your backup on one tape, but you want to do this the faster possible, am I right ?

If your multiplexing is set to one, then only one flux from one client write to one tape at a time.

Are you set multistreaming to on ?
If yes how many jobs limit do you set by client ?

It depend on your kind of drive but if you have a good drive which able to obtain good performance ,you can set multistream, and multiplexing to on.So you will be able to concentrate all you client flux on only one tape.

F@b

 

[sentmemail]

multistreaming is on, and limit to 2 jobs.
i am only backing up 1 client and have 4 streams for it.
how can i put all my backup onto one tape ??

 

[PGPhantom]

There seems to be some confusion...

Multistream - Set up a policy with either multiple clients or multiple drives, scripts etc. Each client and or drive will go to a separate tape drive, if available.

Multiplex - Multiple separate schedules will go to the same drive if initiated at the same time.

So - Multistreaming will make a single client backup faster but will take more tapes. Multiplexing will make multiple clients backup faster - Specifically incremental backups and will use less tapes.

 

[sentmemail]

what value should i set multiplexing to?

 

[F4br1c3]

Hum ... Maybe my english is not perfect so :

There's no confusion :
MultiStream is : How many stream FROM one client (disk)
MultiPlex is : How many stream TO a single Tape drive.

For multistream you have to : set limit to job, and/or declare files with (NEW_STREAM directives) in your policy.

In multiplexing, you can only multiplex data with same retention ( and same schedule name (case sensitive) and same media-server)

If you set multistream on and jobs to 2, how can you reach 4 streams ??

It's allways a #%$¨ to explain this...

Anyway, if you want that your backup take an alone tape you have to multiplex or do a duplication.

F@b

 

[sentmemail]

if i want the backup to be in 1 tape, i should configure mutiplexing to be 4 if i have 4 streams ??

 

[JanEnEm]

It seems 2 me u have a policy for 1 client having 4 disk volumes / filesystems. and u wanna speed up. using 2 tapedrives.

u need to set up the file directives to use NEW_STREAM twice in the definition. Once as the 1st directive, then the smallest and largest filesystem, again NEW_STREAM to generate the 2nd stream to the s2nd drive and finally the 2 other Filesystems.
DONT use multiplexing, set multistream to 2

theoretically this should do the trick.

 

[sentmemail]

if i don't use multiplexing, the backup will not go into 1 tape right?

 

[JanEnEm]

using NEW-STREAM twice, it should go to two tapes, allowing the fastest backup you'd require.
Should you wanna do 1 tape, leave out the NEW_STREAM in your file directives, don't use multistream or multiplexing. Then you have evrything on one tape, but a backup window crossing your window boundaries. So use my previous suggestion.

 

[sentmemail]

i am right to say that culmulative incremental backup will only backup those files that have changed from the last successful fullbackup??