Horrible Write Performance with Smartarray P400 in DL320, DL320s and DL1xx

[PhilipHarvey]

Write cache will be disabled and the performance will be very bad if there is no battery installed. The only way you can enable the write cache is to install a battery.

Once installed the write cache will be automatically enabled, but you can check and modify the settings using the Array Configuration Utility (ACU). You can run this under your operating system (if it is supported) or you can run this from the smartstart CD.

[leisan]

Thanks for the info, do you know where I can find the battery for the controller P400?

[apuritch]

Experiencing similar symptoms with old G5 servers,  the failed battery was found to be the source of performance degradation.  Once the battery failed,  the controller automatically prevented the caching which effectively lowered the write speed to 10% of normal.  During large file copies over the network, the OS would cache data until it consumed just over 50% of system memory at which time the network transfer speed dropped from just over  950Gb/s to under 50Mb/s.   By launching ACU and reconfiguring the RAID controller to perform as though the battery was OK  worked to bring performance back up.   

It may seem odd to post to such an old thread but it's about now that these batteries will be failing as a G5 is over 5 years old.    

[bartek_zgo]

Hi Guys,

I have P400 raid controller and I have the same performance issue on write. I wan to undurstand one thing. If the cache is disabled (system does not detect the battery) I will not obtain performance of the drive? I have SSD drive in RADI 0. It has a performance about 500MB/s. The cache is disabled but why I have performance about 30MB/s? For me the cache can improve the performance but without it, it should work as a simple drive.