Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Aug 16, 2008, at 7:05 AM, Lars Ellenberg wrote:
>> I will post some benchmarks shortly.
>
> thanks, that is appreciated.
Sorry for the loooooong delay in getting back on this - I was trying
to get some useful numbers out of pgbench, but it produces terrible
inconsistent, slow results, even when using local disk on the
underlying DRBD partitions. Watching top on the server pgbench is
hitting makes me think that it cannot fork fast enough to keep up with
the server or something. Doesn't explain how we managed to get really
high numbers on the old server, but meh, bonnie looks good even with -
b so I think we're probably not going to introduce problems upgrading
to this cluster from current production.
I also determined that due to the shared BBWC on the raid card for
both partitions, having a separate WAL partition did not offer any
noticeable boost as it does on standalone scsi disks, and so due to
that and Lars' concerns about separate devices, just made a single 12-
disk RAID10 instead. We have discussed adding a battery-backed
ramdisk (assuming something better than the gigabyte i-ram exists) for
the WAL later. The hardware is two Sun Fire x4240's with 10,000rpm
SAS disks, using an 802.3d aggregate bond crossover interface with two
gigabit interfaces (for 2Gb/s optimal throughput, which degrades
gracefully to 1Gb/s in the case of a network cable failure).
Here are the bonnie numbers:
Without forced sync() calls:
/usr/sbin/bonnie++ -d <partition> -r $(echo "$(free | head -n 2 | tail
-n 1 | \
cut -d ' ' -f 2- | sed -e 's/^ *//g' | cut -d ' ' -f 1 | bc) /
1024" | bc) \
-n 0 -m $(uname -n) -u postgres
Key:
* saturn == old database server (?) from before my time.
* pan == database server as of 2008, 2x 15kRPM disk RAID1, ext3.
* odin == JFS filesystem (10-disk RAID10) with noatime.
* odin-10 == JFS mount on top of DRBD with disconnected secondary,
using DRBD protocol C
* odin-10.2 == JFS mount on top of DRBD with connected secondary,
using DRBD protocol C
* odin-12 == JFS filesystem (12-disk RAID12) with noatime, atop DRBD
with connected secondary, protocol C
Version 1.03 -------Sequential Output------- --Sequential
Input-- --Random-
-Per Chr- --Block-- --Rewrite- -Per Chr- ---
Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec
%CP /sec %CP
saturn 20G 46854 93 70368 22 14434 3 21737 37 24371
2 451.5 0
pan 32G 35401 54 42188 10 22514 3 75288 96 80252
5 586.2 0
odin 63G 46741 97 300976 33 114606 15 49382 93 357564
22 745.2 0
odin-10 63G 47479 98 191399 19 96390 13 47969 91 336319
22 735.1 1
odin-10.2 63G 49968 98 87476 8 83651 11 48463 89 336903
22 752.6 1
odin-12 63G 49785 97 95868 8 86497 10 48247 91 412743
26 735.9 1
With forced sync() calls (better simulates requirements of PostgreSQL
data partition, slower but safer):
/usr/sbin/bonnie++ -d <partition> -r $(echo "$(free | head -n 2 | tail
-n 1 | \
cut -d ' ' -f 2- | sed -e 's/^ *//g' | cut -d ' ' -f 1 | bc) /
1024" | bc) \
-n 0 -m $(uname -n) -u postgres -b
Key:
* saturn == old database server (?) from before my time.
* pan == database server as of 2008, 2x 15kRPM disk RAID1, ext3.
* odin == JFS filesystem (10-disk RAID10) with noatime.
* odin-10 == JFS mount on top of DRBD with disconnected secondary,
using DRBD protocol C
* odin-10.2 == JFS mount on top of DRBD with connected secondary,
using DRBD protocol C
* odin-12 == JFS filesystem (12-disk RAID12) with noatime, atop DRBD
with connected secondary, protocol C
Version 1.03 -------Sequential Output------- --Sequential
Input-- --Random-
-Per Chr- --Block-- --Rewrite- -Per Chr- ---
Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec
%CP /sec %CP
saturn 20G 48322 95 46951 16 16298 3 21725 37 24515
2 322.4 0
pan 32G 32391 49 38968 10 23210 3 75932 97 80357
5 533.2 0
odin 63G 46908 96 275524 31 112355 14 49208 94 340345
20 658.2 1
odin-10 63G 48021 99 182869 18 99332 13 48851 90 333461
21 706.2 1
odin-10.2 63G 48803 96 82507 8 85661 11 48212 89 325545
21 608.4 1
odin-12 63G 50033 98 86856 8 87287 11 48692 92 407978
25 789.1 1
Cheers,
--
Casey Allen Shobe
Database Architect, The Berkeley Electronic Press
cshobe at bepress.com (email/jabber/aim/msn)
http://www.bepress.com | +1 (510) 665-1200 x163