[Gluster-users] quick-read vs. io-cache - was Re: mod_glusterfs?

[Ian Rogers]

On 25/03/2010 00:11, Krishna Srinivas wrote:
> On Wed, Mar 24, 2010 at 10:38 AM, Ian Rogers
> <ian.rogers at contactclean.com>  wrote:
>    
>>
>> In a LAMP situation I'd be wanting to use io-cache but there's also a lot of
>> small files. Having both io-cache and the quick-read cache would just mean
>> the files are double cached - using up twice the memory needed as well as an
>> extra set of memory copies to shuffle things around.
>>      
> Good point :) you will have this double cache problem if you use
> iocache above quickread. But if you use quick read above iocache, only
> quickread caches it (as iocache will never get any open/read calls for
> the small files as quickread fetches all the data in the lookup call)
>
> Hence to avoid the double caching problem always use quickread on top
> of iocache. (i.e in the volfile quickread will be below iocache)
>
> Krishna
>    

Good tip, thanks for that :-)

>
>> like quick-read to be deprecated and it's functionality added to io-cache
>>      

Argh, I hate making punctuation typos!! %-}

Ian