On 11/05/18 23:23, Andreas Joseph Krogh wrote:
På onsdag 09. mai 2018 kl. 22:00:16, skrev Andreas Joseph Krogh
<andreas@xxxxxxxxxx <mailto:andreas@xxxxxxxxxx>>:
På tirsdag 10. april 2018 kl. 19:41:59, skrev Craig James
<cjames@xxxxxxxxxxxxxx <mailto:cjames@xxxxxxxxxxxxxx>>:
On Tue, Apr 10, 2018 at 12:21 AM, Andreas Joseph Krogh
<andreas@xxxxxxxxxx <mailto:andreas@xxxxxxxxxx>> wrote:
På tirsdag 10. april 2018 kl. 04:36:27, skrev Craig James
<cjames@xxxxxxxxxxxxxx <mailto:cjames@xxxxxxxxxxxxxx>>:
One of our four "big iron" (spinning disks) servers
went belly up today. (Thanks, Postgres and pgbackrest!
Easy recovery.) We're planning to move to a cloud
service at the end of the year, so bad timing on this.
We didn't want to buy any more hardware, but now it
looks like we have to.
I followed the discussions about SSD drives when they
were first becoming mainstream; at that time, the
Intel devices were king. Can anyone recommend what's a
good SSD configuration these days? I don't think we
want to buy a new server with spinning disks.
We're replacing:
8 core (Intel)
48GB memory
12-drive 7200 RPM 500GB
RAID1 (2 disks, OS and WAL log)
RAID10 (8 disks, postgres data dir)
2 spares
Ubuntu 16.04
Postgres 9.6
The current system peaks at about 7000 TPS from pgbench.
With what arguments (also initialization)?
pgbench -i -s 100 -U test
pgbench -U test -c ... -t ...
-c -t TPS
5 20000 5202
10 10000 7916
20 5000 7924
30 3333 7270
40 2500 5020
50 2000 6417
FWIW; We're testing
this: https://www.supermicro.nl/products/system/1U/1029/SYS-1029U-TN10RT.cfm
with 4 x Micron NVMe 9200 PRO NVMe 3.84TB U.2 in RAID-10:
$ pgbench -s 100 -c 64 -t 10000 pgbench
scale option ignored, using count from pgbench_branches table (100)
starting vacuum...end.
transaction type: <builtin: TPC-B (sort of)>
scaling factor: 100
query mode: simple
number of clients: 64
number of threads: 1
number of transactions per client: 10000
number of transactions actually processed: 640000/640000
latency average = 2.867 ms
tps = 22320.942063 (including connections establishing)
tps = 22326.370955 (excluding connections establishing)
Sorry, wrong disks; this is correct:
48 clients:
pgbench -s 100 -c 48 -t 10000 pgbench
scale option ignored, using count from pgbench_branches table (100)
starting vacuum...end.
transaction type: <builtin: TPC-B (sort of)>
scaling factor: 100
query mode: simple
number of clients: 48
number of threads: 1
number of transactions per client: 10000
number of transactions actually processed: 480000/480000
latency average = 1.608 ms
tps = 29846.511054 (including connections establishing)
tps = 29859.483666 (excluding connections establishing)
64 clients:
pgbench -s 100 -c 64 -t 10000 pgbench
scale option ignored, using count from pgbench_branches table (100)
starting vacuum...end.
transaction type: <builtin: TPC-B (sort of)>
scaling factor: 100
query mode: simple
number of clients: 64
number of threads: 1
number of transactions per client: 10000
number of transactions actually processed: 640000/640000
latency average = 2.279 ms
tps = 28077.261708 (including connections establishing)
tps = 28085.730160 (excluding connections establishing)
If I'm doing the math properly, then these runs are very short (i.e
about 20s). It would be interesting to specify a time limit (e.g -T600
or similar) so we see the effect of at least one checkpoint - i.e the
disks are actually forced to write and sync the transaction data.
These Micron disks look interesting (pretty good IOPS and lifetime
numbers). However (as usual with Micron, sadly) no data about power off
safety. Do you know if the the circuit board has capacitors?
regards
Mark
