I''m wondering how stable/realiable Xen 2.0 is for running databases in a guest domain with filesystems mounted via LVM. Nicholas ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
I''m wondering how stable/realiable Xen 2.0 is for running databases in a guest domain with filesystems mounted via LVM. I noted the benchmarks used postgres, but I''m wondering about real world use. Thanks. Nicholas ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
testign it has already been fine. I ran 4 databases each in one domain (oracle10g) and it s been amazingly stable. I have not however done performance testing. soon... On Mon, Jan 17, 2005 at 10:55:28PM +1300, Nicholas Lee wrote:> I''m wondering how stable/realiable Xen 2.0 is for running databases in a > guest domain with filesystems mounted via LVM. > > > Nicholas > > > > ------------------------------------------------------- > The SF.Net email is sponsored by: Beat the post-holiday blues > Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. > It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/xen-devel------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
I have run Mysql and Oracle 9i without any problems on 2.0.0 and 2.0.1 , but I didn''t have LVM (don''t think that would create problems) Moshe On Jan 17, 2005, at 11:55 AM, Nicholas Lee wrote:> I''m wondering how stable/realiable Xen 2.0 is for running databases in > a guest domain with filesystems mounted via LVM. > > > Nicholas > > > > ------------------------------------------------------- > The SF.Net email is sponsored by: Beat the post-holiday blues > Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. > It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/xen-devel >------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
On Tue, Jan 18, 2005 at 04:02:01AM +0200, Moshe Bar wrote:> I have run Mysql and Oracle 9i without any problems on 2.0.0 and 2.0.1 > , but I didn''t have LVM (don''t think that would create problems)I would have thought that using loopback/file or NFS VBD would have caused performance issue and lost of database guarantees. Or does a fsync on a File VBD get pushed though to the host (dom0)? Nicholas ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
On Tue, 18 Jan 2005, Nicholas Lee wrote:> On Tue, Jan 18, 2005 at 04:02:01AM +0200, Moshe Bar wrote: > > I have run Mysql and Oracle 9i without any problems on 2.0.0 and 2.0.1 > > , but I didn''t have LVM (don''t think that would create problems) > > I would have thought that using loopback/file or NFS VBD would have > caused performance issue and lost of database guarantees.It definitely causes performance degradation, but that is certainly not the only way to set a domain up, merely the cheapest. The I/O syncer is all going to be managed from DOM0, so if the guest crashes transactional integrity is maintained. If the HW crashes you have the same issues as with ext2. If you want integrity guarantees and high performance you''ll likely want a fibre channel device exported to the guest.> Or does a fsync on a File VBD get pushed though to the host (dom0)?There is no fsync on a block device. An I/O should only be acknowledged when the device commits it. Nonetheless, on Linux I would wager that it stays in the buffer cache until the syncer gets around to flushing it. -Kip> > Nicholas > > > ------------------------------------------------------- > The SF.Net email is sponsored by: Beat the post-holiday blues > Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. > It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/xen-devel >------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
Nicholas Lee wrote:> I''m wondering how stable/realiable Xen 2.0 is for running databases in > a guest domain with filesystems mounted via LVM.In my experience, it''s very reliable for normal usage. I run apache + php + rrdttol + mysql on Xen running on gnbd-imported devices (I was interested in the live migrate feature). It was great for normal usage. The live migrate was rather buggy though. Occasionally (not often) I found domains can''t be accessed at all after migrated. This was with Xen 2.0. I haven''t tested 2.0.3 much. IMHO LVM-based storage should be better (in performance) than gnbd. Regards, Fajar ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
On Mon, 17 Jan 2005, Wim Coekaerts wrote:> testign it has already been fine. I ran 4 databases each in one domain > (oracle10g) and it s been amazingly stable. I have not however done > performance testing. soon...How does O_DIRECT IO to xen block devices work ? Does it make it to disk atomically, or does that still need some patches ? -- "Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it." - Brian W. Kernighan ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> On Mon, 17 Jan 2005, Wim Coekaerts wrote: > > > testign it has already been fine. I ran 4 databases each in one domain > > (oracle10g) and it s been amazingly stable. I have not however done > > performance testing. soon... > > How does O_DIRECT IO to xen block devices work ?I''m not entirely sure quite what O_DIRECT is defined to do. It probably bypasses the guest''s buffer cache OK, and gets turned into IO''s in domain 0 without passing through the buffer cache (unless you''re using a loop file or suchlike). I believe IOs wont be acknowledged to the guest until they''ve been completed in dom0. However, they can be reordered. We probably need to add in a re-order barrier operation on the VBD device channel protocol in order to guarantee ordering where it matters (this would be marginally more efficient than holding back following requests in the guest). Ian ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
On Tue, 2005-01-18 at 20:45 +0000, Ian Pratt wrote:> > On Mon, 17 Jan 2005, Wim Coekaerts wrote: > > > > > testign it has already been fine. I ran 4 databases each in one domain > > > (oracle10g) and it s been amazingly stable. I have not however done > > > performance testing. soon... > > > > How does O_DIRECT IO to xen block devices work ? > > I''m not entirely sure quite what O_DIRECT is defined to do. It > probably bypasses the guest''s buffer cache OK, and gets turned > into IO''s in domain 0 without passing through the buffer cache > (unless you''re using a loop file or suchlike). > > I believe IOs wont be acknowledged to the guest until they''ve > been completed in dom0. However, they can be reordered. We > probably need to add in a re-order barrier operation on the VBD > device channel protocol in order to guarantee ordering where it > matters (this would be marginally more efficient than > holding back following requests in the guest). >To avoid the buffercache problems of loopback images in dom0 you can have dom0 open the loop files with O_DIRECT. This should help performance when using loop files as it eliminates the double buffering.> > Ian > > > ------------------------------------------------------- > The SF.Net email is sponsored by: Beat the post-holiday blues > Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. > It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/xen-devel-- ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel