On Thu, Jan 12, 2017 at 4:44 PM, Raghavendra G <[email protected]> wrote:
> > > On Thu, Jan 12, 2017 at 4:35 PM, Raghavendra G <[email protected]> > wrote: > >> >> >> On Thu, Jan 12, 2017 at 9:20 AM, B.K.Raghuram <[email protected]> wrote: >> >>> cc'ing devel as well for some developer insight.. >>> >>> ---------- Forwarded message ---------- >>> To: gluster-users <[email protected]> >>> >>> >>> I had a question on the expected behaviour of simple distributed volumes >>> when a brick fails for the following scenarios (as in, will the scenario >>> succeed for fail) : >>> >>> - New file creation if that file name hashes to the failed brick >>> >> >> Fails >> >> >>> - New file creation if that file name hashes to one of the remaining >>> functional brick >>> >> >> Succeeds >> >> - New directory creation if that file name hashes to the failed brick >>> >> >> Fails >> >> >>> - New directory creation if that file name hashes to one of the >>> remaining functional brick >>> >> >> Succeeds. Layout is spread only to the functional bricks. Non-functional >> bricks are not part of layout of the directory. In other words files of the >> directory won't be stored in non-functional bricks >> >> >>> - File modifications/deletions if that file name hashes to the failed >>> brick >>> >> >> Fails >> > > Fails mostly. However, let's say if the inode of file has been looked up > when hashed-brick was up, then operations succeed even if hashed-brick goes > down later. > Sorry, I forgot to mention that this can happen only if actual file (data-file) is stored on non-hashed brick and hashed-brick contains a linkto file. If data-file is present on hashed brick and it goes down, access fails always. Following sequence of ops succeed: > > 1. hashed-brick up > 2. Lookup (file) => success > 3. open (file) => success (fd) > 4. hashed-brick goes down > 5. write/read (fd) => success > > Note that if the inode is cached in vfs/kernel after 2, even path based > operations like stat, open, chmod etc can succeed if hashed-brick goes down > immediately after successful lookup. The point is only fresh lookups fail > if hashed brick/subvol is down. > > >> >>> - File modifications/deletions if that file name hashes to one of the >>> remaining functional brick >>> >> >> Succeeds >> >> >>> - Directory renames/deletions if that file name hashes to the failed >>> brick >>> >> >> Fails >> >> >>> - Directory renames/deletions if that file name hashes to one of the >>> remaining functional brick >>> >> >> Fails >> >> >>> >>> >>> _______________________________________________ >>> Gluster-devel mailing list >>> [email protected] >>> http://www.gluster.org/mailman/listinfo/gluster-devel >>> >>> -- >>> Raghavendra G >>> >>> <http://www.gluster.org/mailman/listinfo/gluster-devel> >> >> <http://www.gluster.org/mailman/listinfo/gluster-devel> >> > > > > -- > Raghavendra G > -- Raghavendra G
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