CEPH的参数配置及优化，作者：海风无影
1)主要对比官网参数
http://ceph.com/planet/configure-ceph-rbd-caching-on-openstack-nova/
http://docs.ceph.com/docs/master/rbd/rbd-config-ref/
2)参考http://www.kissthink.com/archive/5153.html实验结果得出结论：
debugging_off: 0 关闭debugg
"filestore_op_threads": "2",最大并行文件系统操作线程数默认为2，推荐调整到1，但写效果只有提高2%左右，一般不调整
"journal_aio": "true",默认是打开的，一定要打开，否则性能差很多,XFS下降10%，EXT4近20%
flush_true: 0 没查到此参数
"ms_nocrc": "false", 调整为true ，提高read 2%左右性能
"osd_disk_threads": "1", 后端磁盘线程数默认为1,不要调整，越大性能越差
"osd_op_threads": "2",Ceph的OSD服务守护程序操作的线程数并行线程数默认为2，推荐调整到4，能提高10%读的性能
3)参考 http://my.oschina.net/renguijiayi/blog/348258
4)xfs 参数调整为 noatime,nodiratime,inode64,nobarrier
mount -t xfs -o noatime,nodiratime,inode64,nobarrierLABEL=/data1 /data1
默认的cache设置
"rbd_cache": "false",
"rbd_cache_writethrough_until_flush":"false",
"rbd_cache_size": "33554432",
"rbd_cache_max_dirty": "25165824",
"rbd_cache_target_dirty": "16777216",
"rbd_cache_max_dirty_age": "1",
"rbd_cache_block_writes_upfront":"false",
最后结合作出调整如下：
修改ceph.conf增加以下字段
修改
在[global]字段增加
mon osd full ratio = .85
mon osd nearfull ratio = .75
osd op threads = 4
journal aio = true
journal dio = true
journal queue max ops = 10000
journal queue max bytes = 335544320
filestore queue max ops = 5000
filestore queue committing max ops = 5000
filestore queue max bytes = 1048576000
ms nocrc = true
[client]
rbd cache = true
rbd cache size = 67108864
rbd cache writethrough until flush = true
修改nova.conf
disk_cachemodes="network=writeback"
Several options can be used depending on the disk type:
file
block
network
mount
Caching methods available:
none,
writethrough,
writeback,
directsync,
writethrough,
unsafe,
更多查看http://ceph.com/planet/configure-ceph-rbd-caching-on-openstack-nova/
http://docs.ceph.com/docs/master/rbd/rbd-config-ref/
修改
sed -i'/#disk_cachemodes/adisk_cachemodes="network=writeback"'/etc/nova/nova.conf
重启后验证：
#virsh dumpxml instance-00000026
默认配置
ceph --admin-daemon/var/run/ceph/ceph-osd.0.asok help
{ "config get": "config get : get the config value",
"config set": "config set [ ...]: set aconfig variable",
"config show": "dump current configsettings",
"dump_blacklist": "dump blacklisted clientsand times",
"dump_historic_ops": "show slowest recentops",
"dump_op_pq_state": "dump op priority queuestate",
"dump_ops_in_flight": "show the opscurrently in flight",
"dump_watchers": "show clients which haveactive watches, and on which objects",
"flush_journal": "flush the journal topermanent store",
"get_command_descriptions": "list availablecommands",
"getomap": "output entire objectmap",
"git_version": "get git sha1",
"help": "list available commands",
"injectdataerr": "inject data error intoomap",
"injectmdataerr": "inject metadataerror",
"log dump": "dump recent log entries to logfile",
"log flush": "flush log entries to logfile",
"log reopen": "reopen log file",
"objecter_requests": "show in-progress osdrequests",
"perf dump": "dump perfcountersvalue",
"perf schema": "dump perfcountersschema",
"rmomapkey": "remove omap key",
"setomapheader": "set omap header",
"setomapval": "set omap key",
"status": "high-level status of OSD",
"truncobj": "truncate object tolength",
"version": "get ceph version"}
查看当前运行的配置 ceph --admin-daemon/var/run/ceph/ceph-osd.0.asok config show
更改前请保存原先配置，对比后的配置
#diff osd0.config_old osd0.config_new
91c91
< "ms_nocrc": "false",
---
> "ms_nocrc": "true",
150,151c150,151
< "mon_osd_full_ratio": "0.95",
< "mon_osd_nearfull_ratio":"0.85",
---
> "mon_osd_full_ratio": "0.85",
> "mon_osd_nearfull_ratio":"0.75",
400c400
< "osd_op_threads": "2",
---
> "osd_op_threads": "4",
551,553c551,553
< "filestore_queue_max_ops": "50",
< "filestore_queue_max_bytes":"104857600",
< "filestore_queue_committing_max_ops":"500",
---
> "filestore_queue_max_ops":"5000",
> "filestore_queue_max_bytes":"1048576000",
> "filestore_queue_committing_max_ops":"5000",
585,586c585,586
< "journal_queue_max_ops": "300",
< "journal_queue_max_bytes":"33554432",
---
> "journal_queue_max_ops":"10000",
> "journal_queue_max_bytes":"335544320",