If it is the same file - Versions 4.0 and higher handoff regions of a file to different hosts to reduce lock contention. Depends on the file size and whether the hosts are accessing the same region of the file as to whether this would help (also depends what version you're running - if >4, you've already got it)
Regards, Scott > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of Schipper, Mark > Sent: Thursday, August 17, 2006 11:08 AM > To: Tharindu Rukshan Bamunuarachchi > Cc: veritas-vx@mailman.eng.auburn.edu > Subject: Re: [Veritas-vx] cluster performance > > > While I have quite a bit of experience with VCS, VXVM and > VXFS....I have no experience with CFS. So I probably can't > help too much with that. But I can take a shot at the storage > side of the equation (lots of experience there too). > > For starters, 40ms is pretty high....but not *that* unusual > of both nodes are trying to access the same file frequently. > Each has to wait its turn, and file locking (that is robust > enough to guard against corruption) takes some time. Your I/O > is still sequential as I understand it. If you want to > determine whether your problem is CFS specific or a storage > problem, here is what I would do: > > - Create a device with the exact same layout as the one that > CFS is using. > - Put VXFS on that device > - Run I/O tests on that device and the CFS device at the same time > - If you see latency on both of them, your problem is not CFS > - If you see latency on the CFS device only, it's probably a > CFS related problem > > Try that. If you end up having latency on both devices I can > probably help you figure out why. If the latency is on the > CFS device only, I probably won't be able to help much. > > > > > -----Original Message----- > From: Tharindu Rukshan Bamunuarachchi [mailto:[EMAIL PROTECTED] > Sent: Wednesday, August 16, 2006 11:38 PM > To: Schipper, Mark > Cc: veritas-vx@mailman.eng.auburn.edu > Subject: Re: [Veritas-vx] cluster performance > > It is CFS. Actually this is very very basic installation. > > We have two nodes connected to disk array. Those two nodes > are installed with VxCFS. > > There are two proceses running independently in two nodes. > They must be writing to same file. We need to CFS to ensure > data conssitecey. > > We have two issues with cluster installation. > > 1. sometimes, max latencey may rise to 50ms to write to disk > 2. Failover time is about 40s in some instances > > Is this normal?? What kind kind of configuration info should > i ask from them?? > > They have suggested following options for dcrease failover > latencey.... > > 1. Reducing intent log file size > 2. mount with noatime option > 3. mount with "mincache=closesync" options > > How will this impact with performace and I/O bandwidth. > Could you pls guide to resolve this ....? > I can ask for more config details from them. > > Thank You! > > Tharindu > > > On 8/17/06, Schipper, Mark <[EMAIL PROTECTED]> wrote: > > > > > > To clarify, are you using Veritas Cluster Filesystem (CFS) > > > > or > > > > Veritas Cluster Server and Veritas File System (VXFS) ?? > > > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of > > Tharindu Rukshan Bamunuarachchi > > Sent: Tuesday, August 15, 2006 9:24 PM > > To: veritas-vx@mailman.eng.auburn.edu > > Subject: [Veritas-vx] cluster performance > > > > We have Veritas cluster at one of our production environment. > > > > Recently while running performance tests we found that , > there is disk > > write latency about 50ms while writing to volume in cluster. > > > > Do you know any pre tested figures about Veritas cluster > file system > > performance.So I can verify configurations of our system. > > > > Cheers! > > Tharindu > > > > > > > > -- > > Tharindu Rukshan Bamunuarachchi > > all fabrications are subject to decay > > _______________________________________________ > > Veritas-vx maillist - Veritas-vx@mailman.eng.auburn.edu > > http://mailman.eng.auburn.edu/mailman/listinfo/veritas-vx > > > > > > > > > > > -- > Tharindu Rukshan Bamunuarachchi > all fabrications are subject to decay > > _______________________________________________ Veritas-vx maillist - Veritas-vx@mailman.eng.auburn.edu http://mailman.eng.auburn.edu/mailman/listinfo/veritas-vx
