Bart Smaalders schrieb:
How big is the database?
After all the data has been loaded, all datafiles together 2.8GB, SGA 320MB.
But I don't think size matters on this problem, since you can already see
during the catalog creation phase that UFS is 2x faster.
Since oracle writes in small block sizes, did you set the recordsize for
ZFS?
recordsize is default (128K). Oracle uses:
db_block_size=8192
db_file_multi_block_read_count=16
I tried with "db_block_size=32768" but the results got worse.
I have just rerun the first parts of my benchmark (database + catalog
creation) with different parameters.
The datafiles will be deleted before each run, so I assume if Oracle
recreates the files again they will already use the modified zfs parameters
(so I don't have to recreate the zpool/zfs).
Below the results (UFS again as the reference point):
UFS written as UFS(forcedirectio?,ufs:blocksize,oracle:db_block_size)
ZFS written as ZFS(zfs:compression,zfs:recordsize,oracle:db_block_size)
These results are now run with memory capping in effect (physmem=262144 (1GB))
db creation catalog creation
UFS(-,8K,8K) [default] 0:41.851 6:17.530
UFS(forcedirectio,8K,8K) 0:40.479 6:03.688
UFS(forcedirectio,8K,32K) 0:48.718 8:19.359
ZFS(off,128K,8K) [default] 0:52.427 13:28.081
ZFS(on,128K,8K) 0:50.791 14.27.919
ZFS(on,8K,8K) 0:42.611 13:34.464
ZFS(off,32K,32K) 1:40.038 15:35.177
(times in min:sec.msec)
So you will win a few percent, but still slower compared to UFS. UFS catalog
creation is already mostly CPU bound: During the ~6 minutes of catalog
creation time the corresponding oracle process consumes ~5:30 minutes of CPU
time. So for UFS there is little margin for improvement.
If you have Oracle installed you can easily check yourself. I have uploaded
my init.ora file and the DB creation script to
http://www.deadcafe.de/perf/
Just modify the variables
. ADMIN (location of the oracle admin files)
. DBFILES (ZFS or UFS where datafiles should be placed)
. and the paths in init.ora
Benchmark results will be in "db.bench" file.
BTW: Why is maxphys still only 56 kByte by default on x86? I have increased
maxphys to 8MB, but not much difference on the results:
db creation catalog creation
ZFS(off,128K,8K) (*) 0:53.250 13:32.369
(*) maxphys = 8388608
Daniel
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