Good questions, Why are there no reply? At 2011-08-16 04:53:50,"Patrick J. LoPresti" <lopresti at gmail.com> wrote: >(FUSE developers: Although my questions are specifically about >Gluster, I suspect most of the answers have more to do with FUSE, so I >figure this is on-topic for your list. If I figured wrong, I >apologize.) > >I have done quite a bit of searching looking for answers to these >questions, and I just cannot find them... > >I think I understand how the Linux page cache works for an ordinary >local (non-FUSE) partition. Specifically: > >1) When my application calls read(), it reads from the page cache. If >the page(s) are not resident, the kernel puts my application to sleep >and gets busy reading them from disk. > >2) When my application calls write(), it writes to the page cache. >The kernel will -- eventually, when it feels like it -- flush those >dirty pages to disk. > >3) When my application calls mmap(), page cache pages are mapped into >my process's address space, allowing me to create a dirty page or read >a page by accessing memory. > >4) When the kernel reads a page, it might decide to read some other >pages, depending on the underlying block device's read-ahead >parameters. I can control these via "blockdev". On the write side, I >can exercise some control with various VM parameters (dirty_ratio >etc). I can also use calls like fsync() and posix_fadvise() to exert >some control over page cache management at the application level. > > >My question is pretty simple. If you had to re-write the above four >points for a Gluster file system, what would they look like? If it >matters, I am specifically interested in Gluster 3.2.2 on Suse Linux >Enterprise Server 11 SP1 (Linux 2.6.32.43 + whatever Suse does to >their kernels). > >Does Gluster use the page cache on read()? On write()? If so, how >does it ensure coherency between clients? If not, how does mmap() >work (or does it not work)? > >What read-ahead will the kernel use? Does posix_fadvise(..., >POSIX_FADV_WILLNEED) have any effect on a Gluster file system? > >I find it hard to imagine that I am the only person with questions >like these... Did I miss a FAQ list somewhere? > >Thanks. > > - Pat >_______________________________________________ >Gluster-users mailing list >Gluster-users at gluster.org >http://gluster.org/cgi-bin/mailman/listinfo/gluster-users -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://supercolony.gluster.org/pipermail/gluster-users/attachments/20130318/c7e06db8/attachment-0001.html>
