Grigory, currently read-ahead intelligently stops doing read-ahead when file is being read randomly. (except it has the overhead of always reading in terms of the page-size with the backend). I am also thinking of makng read-ahead stop reading ahead when file is IO is detected to be read/writes interleaved (to save on the read-ahead losses) 16KB is a very small value. please try out 64KB and 32KB page-sizes, with a page-count of 1 (read ahead just 1 page). with what block size does your application perform IO? avati 2007/12/21, Grigory Shamov <gas@xxxxxx>: > > Dear Amar, > > Thank you for the advice. > > (Actually, I used byte units, like, 16384 for 16KB) > > The thing is, 128KB page-size, while gives full throughput, seems to > kill Rewrite completely, as one could see from the Table down below in > the quote. There I used page-size 128KB and page-count of 2. > > -- > Best regards, > Grigory Shamov > Kazan Science Centre of RAS, > Kazan, Russian Federation > > > Amar wrote: > > Hi, > > With read-ahead 'option page-size 16kB' you may not achieve maximum > > throughput, so, better try 'option page-size 128kB' (Note that 16K is > just > > treated as 16bytes, as the parser needs 'KB' 'MB' 'GB' as the unit, not > K, > > M, or G respectively). > > > > Regards, > > Amar > > > > > On Dec 19, 2007 10:56 PM, Grigory Shamov <gas@xxxxxx> wrote: > >> Dear GlusterFS developers, > >> > Some of the Bonnie++ results are > >> like this: > >> > >> =============================================== > >> FileSystem: Sequential Output , K/sec > >> Per-char Block Rewrite > >> =============================================== > >> NFS 14442 30419 7710 > >> Lustre 16012 35228 19018 > >> GlusterFS 16582 15833 8358 > >> GlusterFS, wb 17988 43774 8409 > >> GlusterFS, ra 18414 15863 1804 > >> GlusterFS, ra, wb 22403 41821 355 > >> =============================================== > >> FileSystem: Sequential Input, K/sec Random > >> Per-char Block seeks, #/s > >> =============================================== > >> NFS 20229 49510 178.8 > >> Lustre 17284 47753 53.0 > >> GlusterFS 16791 16815 161.4 > >> GlusterFS, wb 15304 17438 174.1 > >> GlusterFS, ra 19420 54803 143.3 > >> GlusterFS, ra, wb 19900 54427 144.4 > >> =============================================== > >> > > > > > _______________________________________________ > Gluster-devel mailing list > Gluster-devel@xxxxxxxxxx > http://lists.nongnu.org/mailman/listinfo/gluster-devel > -- If I traveled to the end of the rainbow As Dame Fortune did intend, Murphy would be there to tell me The pot's at the other end.
