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razvan2
3 Argentium

Avamar Backup/Restore parallel threads

Hi,

are there any methods in order to run parallel backup or restore on the same client with avamar ?

Thank you!

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13 Replies
rpervan
3 Argentium

Re: Avamar Backup/Restore parallel threads


Hello Dan,

AFAIK this tweaks could be performed using command line using pre-scripts to involve "avtar" directly on client side, or to use configuration in MCS for different data sets which will trigger different parameters and definitions ...

The thing is that you could involve avtar to handle separate filecache and hashcache files for your multiple Data sets ...

Please be sure that such things could make performance impact on your client machine ...
Also please keep on your mind that  the fractal values in "--filecachemax"  &  "--hashcachemax" must be tuned properly ...

hope this helps ...

.r

razvan2
3 Argentium

Re: Avamar Backup/Restore parallel threads

Hi,

thank you for your answer !

I have a client with ~ 850 GB (large files) and the restore takes ~ 8h.

Could be possible to create 2 or 3 sessions with different content for restore, sessions that runs in parallel ?

Could be any performance improvement in this case ?

Is there any documentation for this scenario ?

The client is a relative powerful UNIX machine.

Thankk you !

Dan

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rpervan
3 Argentium

Re: Avamar Backup/Restore parallel threads

Dan,

> I have a client with ~ 850 GB (large files) and the restore takes ~ 8h.
We are talking about file system (File server)  or DB backup / restore ?  Maybe NDMP ... ????
What exactly ?  Please give us more input ?


> Could be possible to create 2 or 3 sessions with different content for restore, sessions that runs in parallel ?
Same as backup, you can involve 2 avtar processes simultaneity .
to list all backups with specific label
      # avtar --backups --verbose --label=<"Label_Name"> --id=<USER_NAME@/DOMAIN_NAME> --path=<DOMAIN_NAME/CLIENT_NAME>

to list all backups for specific client:
      # avtar --backups --verbose --list --id=<USER_NAME@/DOMAIN_NAME> --path=<DOMAIN_NAME/CLIENT_NAME>

to initiate restore you want ....
       # avtar --extract --label=<"Label_Name"> --id=<USER_NAME@/DOMAIN_NAME> --path=<DOMAIN_NAME/CLIENT_NAME> --target=<"DESTINATION_TARGET_NAME"> <"FILE_YOU_WANT_TO_RESTORE">


> Could be any performance improvement in this case ?
of course!  same as backup. This could increase perf.inpact on Avamar server in 30% too.  

Do you have AVE, Avamar standalone or maybe multi node ?


> Is there any documentation for this scenario ?
huh, not sure.  This is special scenario and some tips and tweak must be customized .

> The client is a relative powerful UNIX machine.
What CPU is used on this Unix.  Can you provide us hardware topology ... network throughput ... etc ..
SPARC, PA-RISC are not optimized for SHA1 operation ... this could be also the reason .
For this tweaks you must consider "ulimit" parameters on OS level . 

rgds,
.r

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razvan2
3 Argentium

Re: Avamar Backup/Restore parallel threads

1. oracle database files

2. So you suggest to take 2 backup sessions with avtar, this will generate 2 different backup label numbers and also restore these 2 backups in parallel with avtar.
But can these 2 sessions runs in parallel, for example started from crontab at 5 min. interval ?

Or, can I restore from the same backup (same sequence number) but with 2 distinct avtar commands for different subfolders ?

3.We have Avamar with RAIN configuration (3 nodes).

4.Network is Gigabit and client is UNIX AIX, pSeries, 16 CPU power5 @2 GHz, 32 GB RAM with external storage (SAN)

5.Ulimit is unlimited

Thank you!

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rpervan
3 Argentium

Re: Avamar Backup/Restore parallel threads

Oracle DB ... ok, this is something different now .

You do not need two processes, but just to tune hash cache on client side ...

let me calculate for you ...  will be back ASAP

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rpervan
3 Argentium

Re: Avamar Backup/Restore parallel threads

Here we are:

1. oracle database files
you are performing dump with RMAN or what .... ??


3.We have Avamar with RAIN configuration (3 nodes).
ok, gr8

4.Network is Gigabit and client is UNIX AIX, pSeries, 16 CPU power5 @2 GHz, 32 GB RAM with external storage (SAN)
ok. perfect!
In this case we need to tune hash cache on client side ...

The formula, then, is for Y GB of database data, the hash cache must be at least Y MB.  for instant:
Using this rule, for a database of 500 GB of database data, the hash cache must be at least 500 MB. The hash cache must be allowed to grow to the next incremental size, 768 MB.

If the client has a few very large files, the default maximum hash cache size may be insufficient. The hash cache almost always needs to be tuned for large databases as the default cache sizes are set for file system backups. You can override the default limits on the size of the hash cache by using the hashcachemax option with the avtar command.
To adequately size the hash cache, set the hashcachemax value as follows: --hashcachemax = 2 x Y where Y is the size of the database to be backed up in gigabytes

in your scenario, we are talking about 850 GB dump ... that means we need to allow hash cache minimally 1536MB or even double (3072MB).
So let us give a try a test backup using "--hashcachemax=-8" value.


OK, please create the "avtar.cmd" flag file to involve tweaks ...
This must be touched in Avamar's "var" directory ... by default should be  "touch /opt/AVMRclnt/var"  directory

now place different parameters on it and re-run the backup .

===========

--filecachemax=-16
--hashcachemax=-8

--stats

--comstats

--verbose=1

===========

please let me know results after test backups ... or maybe log file will be perfect to analyze ... 

Cheers,

.r

razvan2
3 Argentium

Re: Avamar Backup/Restore parallel threads

Hi Rej,

Thank you for these info !

1. No RMAN for the moment, just a cold backup, so just some big files

4. We are talking about ~85 big files, ~ 15 files x 35 GB each and other small files.

Does tuning hash cache help only for backup or also for restore ?

Can we use these attributes (--filecachemax=-16 ... etc.) on a graphical interface (More Options ... -> More ...) ?

Thank you !

Dan

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rpervan
3 Argentium

Re: Avamar Backup/Restore parallel threads

Dan,

>  Does tuning hash cache help only for backup or also for restore ?
No, not fore restore .
Restore perform. coud be let's say average rate 40GB/sec/Storage node ... or max. 50GB/hour/storage node ... so I would say to get back your 850Gb you need aprox.  6-7 hours, max 8 hours .

>  Can we use these attributes (--filecachemax=-16 ... etc.) on a graphical interface (More Options ... -> More ...) ?
Yes, this could be also configured via MCS GUI ... just create separate DataSet for this client only.

rgds,

.r

razvan2
3 Argentium

Re: Avamar Backup/Restore parallel threads

ok, I will try these settings on the next backup window.

Thank you !

Dan

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