extremely slow disk I/O after updating to 12.0
David Demelier
markand at malikania.fr
Wed Jul 3 11:35:07 UTC 2019
Hello folks,
I've upgraded one of my servers to 12.0-RELEASE. Now I'm having
extremely slow performances regarding I/O writes.
I'm doing a cron job which create some tar archive during the night,
usually it takes something like 2-3 hours to complete. Now it does not
finish 12 hours after and I feel the server is much slower in a global
manner. For example when editing files with vim.
The bsdtar process stays a lot in the state zio->io_cv as top indicates
but is not locked as the archive continues to grow (at ridiculous speed
though, something like 4Mo per hour !)
Procstat on the process shows this:
# procstat -kk 46385
PID TID COMM TDNAME KSTACK
46385 101443 bsdtar - mi_switch+0xe1
sleepq_wait+0x2c _cv_wait+0x152 zio_wait+0x9b
dmu_buf_hold_array_by_dnode+0x2ec dmu_read_uio_dnode+0x37
dmu_read_uio_dbuf+0x3b zfs_freebsd_read+0x2d3 VOP_READ_APV+0x78
vn_read+0x195 vn_io_fault_doio+0x43 vn_io_fault1+0x161 vn_io_fault+0x195
dofileread+0x95 sys_read+0xc3 amd64_syscall+0x369 fast_syscall_common+0x101
zpool status indicates that the blocksize is erroneous and that I may
expect performance degradation. But that much is impressive. Can someone
confirm?
# zpool status
pool: tank
state: ONLINE
status: One or more devices are configured to use a non-native block size.
Expect reduced performance.
action: Replace affected devices with devices that support the
configured block size, or migrate data to a properly configured
pool.
scan: none requested
config:
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
gpt/zfs0 ONLINE 0 0 0 block size: 512B
configured, 4096B native
gpt/zfs1 ONLINE 0 0 0 block size: 512B
configured, 4096B native
errors: No known data errors
According to some googling, I must update those pools to change the
block size. However there are no many articles on that so I'm a bit
afraid of doing this. The zfs0 and zfs1 are in raidz.
Any help is very welcome.
Kind regards,
--
David
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