I see! Thanx. 2015-07-19 7:34 GMT+03:00 Michael Mol <[email protected]>:
> That's because they're playing out of Gluster's own playbook: > http://www.gluster.org/community/documentation/index.php/Virt-store-usecase > > The point is that your data corruption issues are vastly more likely to > have come from having write-behind enabled than having read-ahead enabled. > Having write-behind enabled is like juggling your data with with a partner. > Having write-behind disabled is like you and your partner handing data to > each other, rather than tossing it. Having read-ahead disabled is like > asking your partner for a page of data, and having him give you that page > of data. Having read-ahead enabled is like asking your partner for a page > of data, and having him give you a fifty page report, because he thinks you > may need the extra information--except you already made allowances yourself > in asking for that full page of data; the only data you *knew* you needed > was a single table in that page.) > > As another example of why you wouldn't normally need read-ahead enabled in > gluster, I could easily write a small books' worth of theory into an > email detailing the concept further, but I've already given sufficient > information to illustrate the relevant concepts; anything further would be > unnecessary detail I'm only guessing you might need. ;) > > The read-ahead setting is about performance, not about data integrity. > Virtual machines will be running an operating system. That operating system > will be running block-device drivers and filesystem drivers. Both of those > types of drivers have their own tunable concepts of read-ahead, so any > further read-ahead at the gluster layer is unnecessary. > > (I'm not suggesting you enable read-ahead in prod; it's pointless. I'm > just trying to point out that read-ahead shouldn't *break* anything for > you. At the same time, if you enable it, making no other changes, and it > *does* break things, that's something people would want to know about.) > > > On Sat, Jul 18, 2015 at 2:42 PM Roman <[email protected]> wrote: > >> Hi! >> Thanks for reply. >> >> >> https://access.redhat.com/documentation/en-US/Red_Hat_Storage/2.0/html/Quick_Start_Guide/chap-Quick_Start_Guide-Virtual_Preparation.html >> reading this, RH recommends to keep read-ahead off for gluster volumes >> used for VM-s. >> >> 2015-07-18 18:56 GMT+03:00 Michael Mol <[email protected]>: >> >>> I think you'll find it's the write-behind that was killing you. >>> Write-behind opens you up to a number of data consistency issues, and I >>> strongly disrecommend it unless you have a rock-solid infrastructure from >>> the writer all the way to the disk the data ultimately sits on. >>> >>> I bet that if you re-enabled read-ahead, you won't see the problem. Just >>> leave write-behind off. >>> >>> On Sat, Jul 18, 2015, 10:44 AM Roman <[email protected]> wrote: >>> >>> solved after I've added (thanks to Niels de Vos) these options to the >>> volumes: >>> >>> performance.read-ahead: off >>> >>> performance.write-behind: off >>> >>> >>> 2015-07-15 17:23 GMT+03:00 Roman <[email protected]>: >>> >>> hey, >>> >>> I've updated the bug, if some1 has some ideas - share plz. >>> >>> https://bugzilla.redhat.com/show_bug.cgi?id=1242913 >>> >>> >>> 2015-07-14 19:14 GMT+03:00 Kaushal M <[email protected]>: >>> >>> Just a wild guess. What is the filesystem used for the debian 8 >>> installation? It could be the culprit. >>> >>> On Tue, Jul 14, 2015 at 7:27 PM, Roman <[email protected]> wrote: >>> > I've done this way: installed debian8 on local disks using netinstall >>> iso, >>> > created a template of it and then cloned (full clone) it to glusterfs >>> > storage backend. VM boots and runs fine... untill I start to install >>> > something massive (DE ie). Last time it was mate failed to install due >>> to >>> > python-gtk2 package problems (complaing that it could not compile it) >>> > >>> >>> > 2015-07-14 16:37 GMT+03:00 Scott Harvanek <[email protected]>: >>> >> >>> >> What happens if you install from a full CD and not a net-install? >>> >> >>> >> Limit the variables. Currently you are relying on remote mirrors and >>> >> Internet connectivity. >>> >> >>> >> It's either a Proxmox or Debian issue, I really don't think it's >>> Gluster. >>> >> We have hundreds of Jessie installs running on GlusterFS backends. >>> >> >>> >> -- >>> >> Scott H. >>> >> Login, LLC. >>> >> >>> >> >>> >> >>> >> Roman >>> >> July 14, 2015 at 9:30 AM >>> >> Hey, >>> >> >>> >> thanks for reply. >>> >> If it would be networking related, it would affect everything. But it >>> is >>> >> only debian 8 which won't install. >>> >> And yes, i did iperf test between gluster and proxmox nodes. Its ok. >>> >> Installation fails on every node, where i try to install d8. >>> Sometimes it >>> >> goes well (today 1 of 6 tries was fine). Other distros install fine. >>> >> Sometimes installation process finishes, but VM won't start, just >>> hangs >>> >> with errors like in this attached. >>> >> >>> >> >>> >> >>> >> >>> >> -- >>> >> Best regards, >>> >> Roman. >>> >> Scott Harvanek >>> >> July 14, 2015 at 9:17 AM >>> >> We don't have this issue, I'll take a stab tho- >>> >> >>> >> Have you confirmed everything is good on the network side of things? >>> >> MTU/Loss/Errors? >>> >> >>> >> Is your inconsistency linked to one specific brick? Have you tried >>> running >>> >> a replica instead of distributed? >>> >> >>> >> >>> >> >>> >> _______________________________________________ >>> >> Gluster-users mailing list >>> >>> >> [email protected] >>> >> http://www.gluster.org/mailman/listinfo/gluster-users >>> >> Roman >>> >> July 14, 2015 at 6:38 AM >>> >> here is one of the errors example. its like files that debian >>> installer >>> >> copies to the virtual disk that is located on glusterfs storage are >>> getting >>> >> corrupted. >>> >> in-target is /dev/vda1 >>> >> >>> >> >>> >> >>> >> >>> >> >>> >> -- >>> >> Best regards, >>> >> Roman. >>> >> _______________________________________________ >>> >> Gluster-users mailing list >>> >> [email protected] >>> >> http://www.gluster.org/mailman/listinfo/gluster-users >>> >> Roman >>> >> July 14, 2015 at 4:50 AM >>> >> Ubuntu 14.04 LTS base install and then mate install were fine! >>> >> >>> >> >>> >> >>> >> >>> >> -- >>> >> Best regards, >>> >> Roman. >>> >> _______________________________________________ >>> >> Gluster-users mailing list >>> >> [email protected] >>> >> http://www.gluster.org/mailman/listinfo/gluster-users >>> >> Roman >>> >> July 13, 2015 at 7:35 PM >>> >> Bah... the randomness of this issue is killing me. >>> >> Not only HA volumes are affected. Got an error during installation of >>> d8 >>> >> with mate (on python-gtk2 pkg) on Distributed volume also. >>> >> I've checked the MD5SUM of installation iso, its ok. >>> >> >>> >> Shortly after that on the same VE node I installed D7 with Gnome >>> without >>> >> any problem on the HA glusterf volume. >>> >> >>> >> And on the same VE node I've installed D8 with both Mate and Gnome >>> using >>> >> local storage disks without problems. There is a bug somewhere in >>> gluster or >>> >> qemu... Proxmox uses RH kernel btw: >>> >> >>> >> Linux services 2.6.32-37-pve >>> >> QEMU emulator version 2.2.1 >>> >> glusterfs 3.6.4 >>> >> >>> >> any ideas? >>> >> I'm ready to help to investigate this bug. >>> >> When sun will shine, I'll try to install latest Ubuntu also. But now >>> I'm >>> >> going to sleep. >>> >> >>> >> >>> >> >>> >> >>> >> -- >>> >> Best regards, >>> >> Roman. >>> >> _______________________________________________ >>> >> Gluster-users mailing list >>> >> [email protected] >>> >> http://www.gluster.org/mailman/listinfo/gluster-users >>> >> >>> >> >>> > >>> > >>> > >>> > -- >>> > Best regards, >>> > Roman. >>> > >>> > _______________________________________________ >>> > Gluster-users mailing list >>> > [email protected] >>> > http://www.gluster.org/mailman/listinfo/gluster-users >>> >>> >>> >>> -- >>> >>> Best regards, >>> Roman. >>> >>> >>> >>> -- >>> >>> Best regards, >>> Roman. >>> >>> _______________________________________________ >>> Gluster-users mailing list >>> [email protected] >>> http://www.gluster.org/mailman/listinfo/gluster-users >>> >>> >>> >> >> >> -- >> Best regards, >> Roman. >> > -- Best regards, Roman.
_______________________________________________ Gluster-users mailing list [email protected] http://www.gluster.org/mailman/listinfo/gluster-users
