What parallelism factor to pick running nzbackup with -streams option for database backup?
What parallelism factor to pick running nzrestore with -streams option for database restore?
ANSWER:
Pick -streams AUTO for both nzbackup and nzrestore .
Advise: I would recommended to test running multiple nzbackup -streams AUTO concurrently in shell script. This may shrink overall backup time by saturating all available network bandwidth. This option yet to be tested with external backup storage. Stay tuned ...
EXPLANATION:
This empirical test was inspired by poorly performing nzrestore from milti-stream backupset at NPS 7.0 and later releases. At October 2013 it was proven that nzrestore recovery time degrades by factor of 2 with each uptick of streams in source nzbackup dataset. For more details about this experiments see post Netezza: nzbackup & nzrestore on NPS 7.0.
Starting from Netezza NPS 7.2 database restore can be done in multi-stream mode. IBM did a great job improving nzbackup and nzrestore utilities. This test proves that new milti-stream operations show highly improved performance.
TEST CASES:
The matrix below explains various combination running nzbackup followed by nzrestore with -streams option. The test was conducted using host server disk for target work space. The database used for testing has size of 500GB with three dozen of tables consisting of mix datatypes columns.
RESULT:
The greener, the better. The nzbackup -streams AUTO exhibit the best backup performance: "23 min". The recovery performance running nzrestore -streams AUTO is very close to backup speed: "33 min". To validate the data test AUTO vs. AUTO was repeated 8 times showing very close results. The average number was derived for both backup and restore: 23 min / 33 min.
Related documentation: Database backup and restore
Can streams be used if you only have one mounted storage unit?
ReplyDeleteYes, you can.
ReplyDelete