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how to change hash cache
In the OPerational best practice it describes how to change this. Where is this done? I want to increase the hash cache on our excahnge server. In the document it says:
Therefore, 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.
Can someone outline the steps to do this? The Exchange DB is 500GB.
rpervan
266 Posts
2
March 31st, 2011 01:00
Hello dwilk,
Just create "avtar.cmd" flag file to involve "filecachemax" and "hashcachemax" parameters in Avamar's "var" directory >>> "\Program Files\avs\var" and place following on it ....
--filecachemax=-
--hashcachemax=-
Please just calculate the Value according to the formula "--hashcachemax = 2 x Y" you have ... and that is it !
Also please restart the Avamar client after it then run a test backup again.
regards,
-r
rpervan
266 Posts
0
April 5th, 2011 11:00
dwilk1973 , any news on this one maybe ?
regards,
-r
Anonymous
5 Practitioner
5 Practitioner
•
274.2K Posts
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April 12th, 2011 10:00
Hi,
Please refer to the document attached .
Page no : 42 " Hash Cache"
Thanks And Regards,
Ankita Kumar
VCP (VMware Certified Professional)
Technical Support Engineer
CSS WWTS - Avamar
EMC Global Services
North America Support Line: 1-877-534-2867 ext 7857177
Email: ankita.kumar@emc.com
Please note my regular working hours are Monday to Friday, 8am to 5pm EST
Satisfied customers are my top priority. For service feedback & comments, please contact my manager: Annepu_Ravikanth@emc.com
1 Attachment
Best Practices.pdf
dwilk1973
63 Posts
0
April 12th, 2011 10:00
honestly it did not seem to improve backup performance maybe just slightly. Worth knowing how to do though.
rpervan
266 Posts
0
April 12th, 2011 10:00
Which exact values have you set on client' avtar.cmd file ?
rpervan
266 Posts
0
April 12th, 2011 11:00
and how much RAM you have on this machine ?
DB size ?
dwilk1973
63 Posts
0
April 12th, 2011 11:00
8GB RAM and 500GB datastore
dwilk1973
63 Posts
0
April 12th, 2011 11:00
contents of avatar.cmd
--filecachemax=100
--hashcachemax=800
dwilk1973
63 Posts
0
April 12th, 2011 12:00
great summay! So the only values in teh avtar.cmd would be the hash and file cahce settings correct?
rpervan
266 Posts
0
April 12th, 2011 12:00
David,
Maybe you could do following:
- stop Avamar services, processes.
- rename existing "f_cache.dat" and "p_cache.dat" to the "orig_f_cache.dat" and "orig_p_cache.dat"
- modify the "avtar.cmd" with below parameters:
==================
--filecachemax=-16
--hashcachemax=-8
--verbose=2
--stats
--comstats
==================
- start Avamar services again.
This action will re-createt new "f_cache.dat" and "p_cache.dat" files with our settings, and this should works fine then.
If this not work ... please just drop me an email with group summary output and I will review it.
regards,
Rej
rpervan
266 Posts
0
April 12th, 2011 12:00
David,
SUMMARY:
=========
You have: 8GB RAM
DB size: 500GB
RECOMMENDATION
=================
--filecachemax = 2 x N x 44 MB where N is the number of millions of files in the backup. I suppose this is NOT file server, so we would use one in calculation.
--hashcachemax = 2 x Y MB where Y is the size of the database to be backed up in gigabytes
TO DO:
======
According to this please put following in the "avatar.cmd", restart services ... and let us know results .
==================
--filecachemax=-16
--hashcachemax=-8
==================
regards,
Rej
Anonymous
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274.2K Posts
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November 30th, 2014 23:00
avtar.cmd is for windows or any other OS - May i use it for solaris as well
clevya
117 Posts
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December 1st, 2014 01:00
Salvi,
Yes avtar.cmd can be used on all operating systems. I believe in Solaris you will need to place the file in /opt/AVMRclnt/var/avtar.cmd.
Regards,
Adam