Optimizing Backup with HP TurboSTORE

Optimizing backup with HP TurboSTORE/iX
By Paul Raj D. and Bijo S. Kappen
Objective
This paper aims at identifying the software options for optimum backup performance using HP
TurboSTORE/iX with different system configurations and data patterns.
Using TurboSTORE options
The following are the TurboSTORE options that can be considered for performance optimization:
l Using high software compression (COMPRESS=HIGH option):
Typically, this option takes about 80% of CPU time on a single CPU machine for a high-end
target device (e.g. DLT8000) and is CPU intensive. This option gives the best performance
when the system load is very low (e.g. nightly backups when all users/sessions are logged
out). It is recommended not to use this option, if the CPU load is expected to peak during the
backup window. Also, using HIGH compression along with hardware compression may
degrade the backup performance.
l Using low software compression (COMPRESS=LOW option):
Typically, this option takes about 30% of CPU time on a single CPU machine for a high-end
backup device (e.g. DLT8000). To achieve a better performance, this option can be used
along with hardware compression. On a heavily loaded system, it is recommended
to use only
hardware compression.
l Interleaving of files on backup (INTER option):
Interleave option gives best performance:
¡ when files are evenly distributed across disks.
¡ when backup file-set contains many large files.
This option may degrade the backup performance when used with many small files. Presently
TurboSTORE is capable of interleaving up to four files.
l Using different buffer sizes (MAXTAPEBUF option):
TurboSTORE supports 16KB and 32KB buffer sizes. Default buffer size is 16KB. For backups
to remote devices, only 16KB is supported. Typically, performance doubles with 32KB buffer
(MAXTAPEBUF) when compared to 16KB.
l Doing parallel backup (STORESET option):
Doing parallel backups helps to reduce the backup window by several folds, especially on
multi-processor systems. When using high-end devices like DLT8000, a general rule for doing
parallel backup is to have one less target (tape) drive in the parallel set than the number of
processors. For example, on a 4-way system, perform a 3-device parallel backup. This is
because STORE uses two additional processes to control the overall backup. If you are doing
a three device parallel backup, it is possible that you could get three times the performance of
a single backup on a four-way multiprocessor system.
On a single processor system, one may not see the same performance improvement with
parallel backups. However, depending on the system configuration, one should still see an
increased backup performance.
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White Paper : DLT Performance with TurboSTORE
10/17/2008
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