On 03/14/2013 10:44 AM, Greg Farnum wrote:
On Thursday, March 14, 2013 at 8:20 AM, Sage Weil wrote:
On Thu, 14 Mar 2013, Huang, Xiwei wrote:
Hi, all,
I noticed that CephFS fails to support Direct IO for blocks larger than 8MB, say:
sudo dd if=/dev/zero of=mnt/cephfs/foo bs=16M count=1 oflag=direct
dd: writing `mnt/cephfs/foo: Bad address
1+0 records in
0+0 records out
0 bytes (0 B) copied, 0.213948 s, 0.0 kB/s
My version Ceph is 0.56.1.
??I also found the bug has been already reported as Bug #2657.
Is this fixed in the new 0.58 version?
I'm pretty sure this is a problem on the kernel client side of things, not
the server side (which by default handles writes up to ~100MB or so). I
suspect it isn't terribly difficult to fix, but hasn't been prioritized...
sage
My guess too. Are direct IO writes of that size a common thing or of great import to you?
Either way, a comment on the tracker saying you've run into it will promote it up when we're doing bug scrubs and backlog reviews. :)
-Greg
I imagine we'll see some applications doing large direct IO writes like
this in the HPC space.
Mark
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
