Thanks for the pointer, James. In some ways the symptom seems different, since I was seeing correct output on other nodes, but not on the node where it was being generated, but otherwise it might well be a match. I may try turning quickread off on my volumes to see if it helps. .. Lana (lana.deere at gmail.com) On Mon, Nov 1, 2010 at 10:31 AM, Burnash, James <jburnash at knight.com> wrote: > Hi Lana. > > Looks like you may have run into this bug as well: > > http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2027 > > James Burnash, Unix Engineering > > -----Original Message----- > From: gluster-users-bounces at gluster.org [mailto:gluster-users-bounces at gluster.org] On Behalf Of Lana Deere > Sent: Friday, October 29, 2010 5:06 PM > To: gluster-users at gluster.org > Subject: concurrent write and read to the same file > > GlusterFS 3.1.0, distributed volumes, rdma transport, CentOS 5.4/5.5. > > I was doing "tail -f" on a log file while the program generating it > was running and noticed some strange behavior. ?I wasn't able to > reproduce exactly the same strange behavior, but here is some which > did reproduce for me reliably. ?This is a small perl program producing > a bit of output every few seconds: > ? ?$| = 1; > ? ?for ($i=0; $i < 100; ++$i) { > ? ? ? ?printf("This is line $i\n"); > ? ? ? ?sleep(3); > ? ?} > > If I run it with output sent to a gluster volume, > ? perl foo.pl > bar > it works fine: "bar" has the right content after the script > terminates, or if I kill the script while it runs "bar" has a valid > partial output. > > While the perl script is running, if I log into a different host which > can see that volume and do "tail -f bar" that also works fine: every > few seconds, the next line of output appears. > > However, while the perl script is running if I do "tail -f bar" from > the same host as the script is running on, it will print me the > current end of the file but then it will hang without producing any > subsequent output. ?This is true whether or not I have a tail running > on a different host concurrently. > > The tail on the same host as the script will correctly notice that the > file was reset if I kill and restart the perl script while leaving the > tail running. ?Then it prints the first line, but at that point it > hangs again. > > Anyone else seeing this? ?Any ideas what might be reasons why? > > Thanks! > > > .. Lana (lana.deere at gmail.com) > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://gluster.org/cgi-bin/mailman/listinfo/gluster-users > > > DISCLAIMER: > This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this in error, please immediately notify me and permanently delete the original and any copy of any e-mail and any printout thereof. E-mail transmission cannot be guaranteed to be secure or error-free. The sender therefore does not accept liability for any errors or omissions in the contents of this message which arise as a result of e-mail transmission. > NOTICE REGARDING PRIVACY AND CONFIDENTIALITY Knight Capital Group may, at its discretion, monitor and review the content of all e-mail communications. http://www.knight.com >
