[CentOS] To discard... or not to discard...

Wed Dec 4 21:59:39 UTC 2013
Leon Fauster <leonfauster at googlemail.com>

Am 04.12.2013 um 19:20 schrieb Akemi Yagi <amyagi at gmail.com>:
> On Wed, Dec 4, 2013 at 9:20 AM, Leon Fauster <leonfauster at googlemail.com> wrote:
>> Am 04.12.2013 um 17:08 schrieb John Doe <jdmls at yahoo.com>:
>>> I just recently read a post about SSD triming (discard vs fstrim):
>>> 
>>> http://www.howtogeek.com/176978/ubuntu-doesnt-trim-ssds-by-default-why-not-and-how-to-enable-it-yourself/So far I used discard on all my SSDs.
>>> Now I am wondering if it is really worth it to switch them all to a crontabed fstrim...
>>> Anyone made the switch yet?
>> 
>> https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html-single/Storage_Administration_Guide/#idm34358800
>> 
>> "Red Hat recommends batch discard operations ..." (fstrim)
>> 
> 
> In addition to the RH doc referenced by LF, I found this web page useful:
> 
> http://blog.neutrino.es/2013/howto-properly-activate-trim-for-your-ssd-on-linux-fstrim-lvm-and-dmcrypt/


interesting article. it shows the passthrough of the discard option with 
dm-crypt involved. rhel seems to not provide such "dm-crypt/trim" support. 

https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/ch-ssd.html#ssddeploy

"The only DM targets that do not support discards are dm-snapshot, dm-crypt, and dm-raid45."

maybe with the next minor release?

--
LF