Hi,
I am experiencing very slow raw read performance from mirrored ZVOL (about 60 MiB/s).
Used system: FreeBSD 10-BETA2
Used disks: 2x ST2000DM001-1CH164 CC26 (2TB 4k sectors)
I created a GPT for each disk as follows:
Than I created zfs pool tank as mirror:
Than I exported this ZVOL to my Windows 8 client via iSCSI over a direct 1Gbit connection.
I created an NTFS file system over an iSCSI exported volume with 8k block size. I did some tests and Read/Write is clipped around 50-60 MiB/s. When I added the ZIL to tank/iscsi I can reach circa 115 MiB/s write speed (so the network shouldn't be the problem), which is great, but read speed is still only 50-60 MiB/s. Also dd from /dev/zvol/tank/iscsi to /dev/null is clipped at 60 MiB/s.
I am using the default ZFS sysctl setting.
Output of
I would be grateful for any advice how to improve the read performance.
I am experiencing very slow raw read performance from mirrored ZVOL (about 60 MiB/s).
Used system: FreeBSD 10-BETA2
Used disks: 2x ST2000DM001-1CH164 CC26 (2TB 4k sectors)
I created a GPT for each disk as follows:
Code:
gpart create -s gpt ada0
gpart create -s gpt ada1
gpart add -t freebsd-zfs -a 4k -b 1M -l bay3 ada0
gpart add -t freebsd-zfs -a 4k -b 1M -l bay4 ada1
Than I created zfs pool tank as mirror:
Code:
zpool create tank mirror gpt/bay3 gpt/bay4
zfs create -V 1770G tank/iscsi
Than I exported this ZVOL to my Windows 8 client via iSCSI over a direct 1Gbit connection.
Code:
portal-group pg0 {
discovery-auth-group no-authentication
listen 192.168.0.1
}
target iqn.xxx.server:target0 {
auth-group no-authentication
portal-group pg0
lun 0 {
path /dev/zvol/tank/iscsi
}
}
I created an NTFS file system over an iSCSI exported volume with 8k block size. I did some tests and Read/Write is clipped around 50-60 MiB/s. When I added the ZIL to tank/iscsi I can reach circa 115 MiB/s write speed (so the network shouldn't be the problem), which is great, but read speed is still only 50-60 MiB/s. Also dd from /dev/zvol/tank/iscsi to /dev/null is clipped at 60 MiB/s.
I am using the default ZFS sysctl setting.
Output of
gstat
for devices under read
Code:
dT: 1.002s w: 1.000s
L(q) ops/s r/s kBps ms/r w/s kBps ms/w %busy Name
11 410 410 52503 10.2 0 0 0.0 75.5| zvol/tank/iscsi
2 959 959 28136 1.7 0 0 0.0 48.0| gpt/bay4
4 945 945 28239 1.8 0 0 0.0 53.6| gpt/bay3
I would be grateful for any advice how to improve the read performance.