gluster性能相關中繼器默認值說明

• 2020 年 2 月 1 日
• 筆記

一、性能相關中繼器

write-behind, read-ahead, io-cache, quick-read, open-behind, stat-prefetch(md-cache), io-threads(默認server端)

以上中繼器默認全部開啟，symlink-cache默認關閉。

NFS相關性能優化中繼器

默認開啟：

performance.nfs.write-behind

默認關閉：

performance.nfs.read-ahead performance.nfs.io-cache performance.nfs.quick-read performance.nfs.stat-prefetch performance.nfs.io-threads performance.force-readdirp

二、默認配置及默認值

1、默認配置中繼

在./vols/tank/tank-fuse.vol（客戶端）文件中，默認會配置如下中繼器：

dht和性能相關的write-behind, read-ahead, io-cache, quick-read, open-behind, stat-prefetch(md-cache).

在./vols/tank/tank.node1.data-disk3.vol同類（伺服器端）文件中，默認會設置如下中繼器參數：

posix、access-control、locks、io-threads、index、maker

2、默認配置項值

cache-size

io-cahce：cache-size：默認32MB

Size of the read cache

quick-read：cache-size：默認128MB

Size of the read cache

gluster volume set tank cache-size 32MB 該命令導致的cache-size更新包含兩個部分，一個是io-cache里對應的cache大小，一個是quick-read里的cache大小。 從源程式碼上看，這兩個cache-size對應同一個key，所以會出現一改全改的現象，應該是一個bug。

read-ahead：page-count：默認值4

key為performance.read-ahead-page-count，可以通過該選項進行設置。 gluster volume set tank read-ahead-page-count 4 Number of pages that will be pre-fetched

write-behind："cache-size"或者"window-size"：默認值1MB

key為performance.write-behind-window-size，可以通過該選項進行設置。 gluster volume set tank write-behind-window-size 1MB Size of the write-behind buffer for a single file (inode).

io-threads：thread-count：默認16

key：performance.io-thread-count gluster volume set tank io-thread-count 16 Number of threads in IO threads translator which perform concurrent IO operations at a given time 該配置保存在/vols/tank/tank.node1.data-disk3.vol同類文件中。

md-cache：md-cache-timeout：默認值1（亦stat-prefetch）

gluster volume set tank md-cache-timeout 1 該操作會更改md-cache中繼器md-cache-timeout選項的默認值 Time period after which cache has to be refreshed

io-cache：cache-timeout：默認值1

key：performance.cache-refresh-timeout gluster volume set tank cache-refresh-timeout 1 cache-timeout：The cached data for a file will be retained till 'cache-refresh-timeout' seconds, after which data re-validation is performed.

備註：默認參數基於GlusterFS 3.4.5