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NFS poor performance on some vm's

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krutoiadmin

I have a Cassandra cluster of 6 VMs, each of these VMs has an NFS share attached, the last few weeks the backups from some nodes began to fall off, began debugging, as a result I tried to write zeros, that's what happened in the end:

1vm

time dd if = / dev / zero of = foel bs = 16k count = 128k
131 072 + 0 records in
131072 + 0 records out
2147483648 bytes (2.1 GB) copied, 4.23151 s, 507 MB / s

real 0m4.239s
user 0m0.008s
sys 0m1.593s

2vm
time dd if = / dev / zero of = foel bs = 16k count = 128k
131 072 + 0 records in
131072 + 0 records out
2147483648 bytes (2.1 GB) copied, 4.83356 s, 444 MB / s

real 0m4.839s
user 0m0.005s
sys 0m1.544s

3vm
time dd if = / dev / zero of = foel bs = 16k count = 128k
131072 + 0 records in
131072 + 0 records out
2147483648 bytes (2.1 GB) copied, 56.0399 s, 38.3 MB / s

real 0m56.054s
user 0m0.138s
sys 0m1.741s

4vm
time dd if = / dev / zero of = foel bs = 16k count = 128k
131072 + 0 records in
131072 + 0 records out
2147483648 bytes (2.1 GB) copied, 6.88073 s, 312 MB / s

real 0m6.887s
user 0m0.125s
sys 0m1.862s

5vm
time dd if = / dev / zero of = foel bs = 16k count = 128k
131 072 + 0 records in
131072 + 0 records out
2147483648 bytes (2.1 GB) copied, 48.762 s, 44.0 MB / s

real 0m48.771s
user 0m0.114s
sys 0m1.740s

6vm
time dd if = / dev / zero of = foel bs = 16k count = 128k
131072 + 0 records in
131072 + 0 records out
2147483648 bytes (2.1 GB) copied, 5.74801 s, 374 MB / s

real 0m5.754s
user 0m0.104s
sys 0m1.744s

As you can see, at 5 and 3 vm, writing is very slow.

Mount options are the same on all VMs:

tac / etc / fstab
172.24.5.229:/kosandra_bekap / opt / cassandra-backup nfs rw, noatime 0 0

I can't ping the nfs, pings are closed.

33
0 + 0
nfs
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