hi guys/gals
I realize that this question must have been asked before, I
sroogled and found some posts on the web on how to
tweak/tune gluster, however..
What I hope is that some experts and/or devel could write a
bit more, maybe compose a doc on - How to investigate and
trouble gluster's speed-performance bottleneck.
Why I think such a thorough guide would be important? Well..
I guess many of us wonder when we look at how "raw" fs vs
glusterfs does then we wonder - how come!?
I know such a comparison is oversimplification or maybe even
unfair but when I see such a gigantic performance difference
then I think, I hope - it must be possible to help with a
detective work to unravel any bottlenecks that may hamper
glusterfs so badly that almost to a point that one
wonders... what is the point.
I did today such a oversimplified test, I used dbench on a
raw xfs lvm raid0 four ssd pvs (no hardware raid)
$ dbench -t 60 10
...
8 of 10 processes prepared for launch 0 sec
10 of 10 processes prepared for launch 0 sec
releasing clients
10 21573 1339.94 MB/sec warmup 1 sec latency
35.500 ms
10 50505 1448.58 MB/sec warmup 2 sec latency
10.027 ms
10 78424 1467.54 MB/sec warmup 3 sec latency
8.810 ms
10 105338 1462.94 MB/sec warmup 4 sec latency
19.670 ms
10 134820 1488.04 MB/sec warmup 5 sec latency
11.237 ms
10 164380 1505.12 MB/sec warmup 6 sec latency
4.007 ms
...
Throughput 1662.91 MB/sec 10 clients 10 procs
max_latency=38.879 ms
Cluster hosts 9 vols, each vol on three peers in replica
mode. Generally, but also most of the time vols utilization
is really low, data would be regular office work, read
randomly single files.
Peers are connected via net switch stack, each peer connects
to stack via two-port lacp 1GB link, jumbo mtu.
So I do do same dbench on one of the vols:
...
8 of 10 processes prepared for launch 0 sec
10 of 10 processes prepared for launch 0 sec
releasing clients
10 98 45.41 MB/sec warmup 1 sec latency
113.146 ms
10 212 41.52 MB/sec warmup 2 sec latency
93.800 ms
10 343 41.23 MB/sec warmup 3 sec latency
53.545 ms
10 468 41.06 MB/sec warmup 4 sec latency
54.450 ms
10 612 41.89 MB/sec warmup 5 sec latency
152.659 ms
10 866 35.99 MB/sec warmup 6 sec latency
31.377 ms
10 1074 32.74 MB/sec warmup 7 sec latency
39.923 ms
10 1307 29.77 MB/sec warmup 8 sec latency
42.388 ms
...
Throughput 15.3757 MB/sec 10 clients 10 procs
max_latency=54.371 ms
So yes.. gee.. how can I make my gluster-cluster faster???
many thanks, L.
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