I am running several fileservers using this controller, filesystem and disk setup.
All of them are suffering from poor write performance, once the 256MB BBU Write Cache is full i get really high iowait (>40) and the write speed goes down to a few MB/s
It get's even worse if the servers are encountering medium to heavy reads while writing.
I am looking for suggestions on how to tweak the controller or the filesystem to improve write performance.
Some data about the Raid Array and Controller:
RAID Level: Primary-5, Secondary-0, RAID Level Qualifier-3 Size:5.456 TB State: Optimal Stripe Size: 64 KB Number Of Drives:4 Span Depth:1 Default Cache Policy: WriteBack, ReadAdaptive, Cached, No Write Cache if Bad BBU Current Cache Policy: WriteBack, ReadAdaptive, Cached, No Write Cache if Bad BBU Access Policy: Read/Write Disk Cache Policy: Enabled Encryption Type: None Product Name : PERC 6/i Integrated FW Version : 1.22.12-0952 BIOS Version : 2.04.00
Data about the filesystem:
Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Default mount options are used and the filesystem was created using the default options of the mkfs.ext4 command.
Just to illustrate my use-case i will describe what these servers are doing
They are serving files via lighttpd at 40-80 MB/s, new files are periodically being downloaded to the servers via ftp.
The files are between 800MB and 6GB.
Serving the files works great, without any noticable IOWait, but everytime the ftp transfers kick in to get new files you can see it really struggeling.
as requested, here is the bonnie++ output:
Version 1.96 ------Sequential Output------ --Sequential Input- --Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP XXXXXXX 8G 580 99 94284 14 61903 9 2853 83 189033 11 420.5 8 Latency 14004us 825ms 1548ms 105ms 202ms 98036us Version 1.96 ------Sequential Create------ --------Random Create-------- XXXXXXX -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 5 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ Latency 406us 535us 598us 374us 21us 60us
The disks in use are D-WMAY03176700WDC WD2002FAEX-007BA0 on all servers