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HOW TO INCREASE THE SAN SPEED

Created: 02 Apr 2010 | 9 comments
 
WHAT HAPPENS WHEN " DISABLE THE REMOVABLE STORAGE SERVICE" ?

CAN WE INCREASE THE SAN BACKUP SPEED BY DISABLING THE REMOVABLE STORAGE SERVICE ?

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qiblatain's picture

BY EDITING THE REGISTRY RELATED TO TAPE DRIVES SERVICES, CAN WE INCREASE THE SAN BACKUP SPEED.

IF POSSIBLE, PLEASE GIVE THE SUGGESTIONS.

THANKS.
Will Restore's picture

Issue:  This service will interfere with VERITAS NetBackup (tm) and cause various issues with tape drives and tape libraries. Tape drives can go down and there maybe issues when incorrect tapes are loaded into the tape drives.

Additional Information:
The service called Removable Storage needs to be set to disabled. If the service is set to Automatic or Manual it will be either running or will start running. This service will attempt to manage the tape library or tape drives and can cause potential tape drive or tape library issues. It is recommended that the service be disabled on all servers that can see the tape drives and tape library. This is especially critical in a SAN environment when there are multiple servers that could be zoned to see the tape drives and tape library.

http://seer.entsupport.symantec.com/docs/274991.htm

Will Restore -- where there is a Will there is a way

Marianne's picture

The NBU Performance Tuning Guide is a good starting point if you want to increase performance.

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

Rakesh Khandelwal's picture

Performance Guide is always a good start point but before that you must understand your hardware capabilities, SAN topology etc.

What kind of speed are you getting and what speed do you want to get?
you can play with device drivers, set buffer settings, DATA_BUFFER_SIZE and NUMBER_DATA_BUFFER etc.... look at your SAN topology you may be limited by ISL between switches.

qiblatain's picture

I am getting the average speed of 9 MB/Sec  for the SAN backups. It starts from 50 mb/sec, sometime from 80 mb/sec, sometimes 60,, but suddenly starts to decrease to 35 mb/sec and then at 17 mb/sec it retains for a long time.. at the end the average speed becomes 9 mb/sec. which is too slow.

we have already played with the Device buffer and currently we have below values of buffer

DATA_BUFFER_SIZE =  262144
NUMBER_DATA_BUFFER = 128
NET_BUFFER_SZ = 2097152

At least we want minimum of 80 mb/sec, or 90 mb/sec, or even more............ (our Tape writing speed is 80mb/sec)

Taqadus Rehman's picture

recently we achived 75MB/sec by just tuning DATA_BUFFER_SIZE, NUMBER_DATA_BUFFER, NET_BUFFER_SIZE on media servers, if you are backing up lots of small files then speed will also be slow but not that much u getting at the moment. 

Regards, Taqadus Rehman

qiblatain's picture

Dear Taqadus,

What were the previous speed you were getting. How much difference of speed you got.

Thanks & Regards,
Qiblatain

jim dalton's picture

Your data profile is important as is the rest of your infrastructure.
Create yourself a large uncompressible file in its own directory and back only that up. What perf do you get? Move it to,different storage eg local, repeat.
Netb has problems when it comes to large numbers of small files as theres a lot of management (open , close, register, ...) for each file and very little data reading, hence multigbyte files are very rapid in the context of the whole process.
Use bpbkar to read the file off disk, how does that compare? Youwont be able to go any faster than the biggest bottleneck.

Taqadus Rehman's picture

Qiblatain,

previously we were getting around 12-30mb/sec for different media servers but now we streamlined all the backups to 75mb/sec

Regards, Taqadus Rehman