[CentOS] Centos/Linux Disk Caching, might be OT in some ways

Ross Walker rswwalker at gmail.com
Thu Jan 28 14:48:44 UTC 2010


On Jan 27, 2010, at 7:50 PM, Christopher Chan <christopher.chan at bradbury.edu.hk 
 > wrote:

>
>> Sorry to be the bearer of bad news, but on top of LVM on CentOS/RHEL
>> the best assurance your going to get is fsync(), meaning the data is
>> out of the kernel, but probably still on disk write cache. Make sure
>> you have a good UPS setup, so the disks can flush after main power  
>> loss.
>
> Or turn off write caching...

Have you tried doing any kind of write with write caching turned off?  
It is so horribly slow to make it almost useless.

If you need to turn write-caching off then I would start looking at  
SSD drives with capacitor based caches.

-Ross



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