Recently, I want to test performance benefit of rbd cache, i cannot get
obvious performance benefit at my setup, then I try to make sure rbd cache is
enabled, but I cannot get rbd cache perf counter. In order to identify how to
enable rbd cache perf counter, I setup a simple setup(one client hosted vms,
one ceph cluster with two OSDs, each osd has a SSD partition for journal.),
then build ceph-0.67.4.
My ceph.conf shows as bellows:
[global]
debug default = 0
log file = /var/log/ceph/$name.log
max open files = 131072
auth cluster required = none
auth service required = none
auth client required = none
rbd cache = true
[mon.a]
host = {monitor_host_name}
mon addr = {monitor_addr}
[osd.0]
host = {osd.0_hostname}
public addr = {public_addr}
cluster addr = {cluster_addr}
osd mkfs type = xfs
devs = /dev/sdb1
osd journal = /dev/sdd5
[osd.1]
host = {osd.1_hostname}
public addr = {public_addr}
cluster addr = {cluster_addr}
osd mkfs type = xfs
devs = /dev/sdc1
osd journal = /dev/sdd6
after ceph cluster is built, I create a rbd image with rbd create -size 10240
-new-format test
then use virsh to start a vm, below is my vm xml file
<domain type='qemu'>
<name>test</name>
<memory unit='KiB'>524288</memory>
<currentMemory unit='KiB'>524288</currentMemory>
<vcpu placement='static'>1</vcpu>
<os>
<type arch='x86_64' machine='pc-1.2'>hvm</type>
<boot dev='hd'/>
</os>
<features>
<acpi/>
<apic/>
</features>
<cpu mode='host-model'>
<model fallback='allow'/>
</cpu>
<clock offset='utc'>
<timer name='pit' tickpolicy='delay'/>
<timer name='rtc' tickpolicy='catchup'/>
</clock>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>destroy</on_crash>
<devices>
<emulator>/usr/bin/qemu-system-x86_64</emulator>
<disk type='file' device='disk'>
<driver name='qemu' type='qcow2' cache='none'/>
<source file='/root/disk'/>
<target dev='vda' bus='virtio'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x04'
function='0x0'/>
</disk>
<disk type='network' device='disk'>
<driver name='qemu' type='raw' cache='writeback'/>
<source protocol='rbd'
name='rbd/test:rbd_cache=true:rbd_cache_writethrough_until_flush=true'/>
<target dev='vdb' bus='virtio'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x06'
function='0x0'/>i
</disk>
<graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'
keymap='en-us'>
<listen type='address' address='0.0.0.0'/>
</graphics>
</devices>
</domain>
Then I add a rbd admin socket in ceph.conf on my client, below is the config
[global]
auth cluster required = none
auth service required = none
auth client required = none
rbd cache = true
rbd cache writethrough until flush = true
[client]
admin socket=/var/run/ceph/rbd-$pid.asok
[mon.a]
host = {monitor_host_name}
mon addr = {monitor_host_addr}
then I checked rbd cache perf counter by this socket, but the output did not
get any rbd cache statistics
ceph --admin-daemon /var/run/ceph/rbd-3526.asok perf dump output
{ "objecter": { "op_active": 0,
"op_laggy": 0,
"op_send": 0,
"op_send_bytes": 0,
"op_resend": 0,
"op_ack": 0,
"op_commit": 0,
"op": 0,
"op_r": 0,
"op_w": 0,
"op_rmw": 0,
"op_pg": 0,
"osdop_stat": 0,
"osdop_create": 0,
"osdop_read": 0,
"osdop_write": 0,
"osdop_writefull": 0,
"osdop_append": 0,
"osdop_zero": 0,
"osdop_truncate": 0,
"osdop_delete": 0,
"osdop_mapext": 0,
"osdop_sparse_read": 0,
"osdop_clonerange": 0,
"osdop_getxattr": 0,
"osdop_setxattr": 0,
"osdop_cmpxattr": 0,
"osdop_rmxattr": 0,
"osdop_resetxattrs": 0,
"osdop_tmap_up": 0,
"osdop_tmap_put": 0,
"osdop_tmap_get": 0,
"osdop_call": 0,
"osdop_watch": 0,
"osdop_notify": 0,
"osdop_src_cmpxattr": 0,
"osdop_pgls": 0,
"osdop_pgls_filter": 0,
"osdop_other": 0,
"linger_active": 0,
"linger_send": 0,
"linger_resend": 0,
"poolop_active": 0,
"poolop_send": 0,
"poolop_resend": 0,
"poolstat_active": 0,
"poolstat_send": 0,
"poolstat_resend": 0,
"statfs_active": 0,
"statfs_send": 0,
"statfs_resend": 0,
"command_active": 0,
"command_send": 0,
"command_resend": 0,
"map_epoch": 0,
"map_full": 0,
"map_inc": 0,
"osd_sessions": 0,
"osd_session_open": 0,
"osd_session_close": 0,
"osd_laggy": 0},
"throttle-msgr_dispatch_throttler-radosclient": { "val": 0,
"max": 104857600,
"get": 11,
"get_sum": 5655,
"get_or_fail_fail": 0,
"get_or_fail_success": 0,
"take": 0,
"take_sum": 0,
"put": 11,
"put_sum": 5655,
"wait": { "avgcount": 0,
"sum": 0.000000000}},
"throttle-objecter_bytes": { "val": 0,
"max": 104857600,
"get": 0,
"get_sum": 0,
"get_or_fail_fail": 0,
"get_or_fail_success": 0,
"take": 0,
"take_sum": 0,
"put": 0,
"put_sum": 0,
"wait": { "avgcount": 0,
"sum": 0.000000000}},
"throttle-objecter_ops": { "val": 0,
"max": 1024,
"get": 0,
"get_sum": 0,
"get_or_fail_fail": 0,
"get_or_fail_success": 0,
"take": 0,
"take_sum": 0,
"put": 0,
"put_sum": 0,
"wait": { "avgcount": 0,
"sum": 0.000000000}}}
Qemu version: qemu-system-x86_64 --version
QEMU emulator version 1.2.0 (qemu-kvm-1.2.0+noroms-0ubuntu2.12.10.5, Debian),
Copyright (c) 2003-2008 Fabrice Bellard
Can anybody help me, any hints will be appreciated ?
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