tag:blogger.com,1999:blog-9095593736735388687.post5866485786354985785..comments2012-12-09T21:15:40.454-08:00Comments on brehak: LVM2bbloghttp://www.blogger.com/profile/12349409386285881725noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-9095593736735388687.post-17837836750113530742008-08-16T03:08:00.000-07:002008-08-16T03:08:00.000-07:00Hello Pat,Thanks for your post.We gave up trying t...Hello Pat,<BR/><BR/>Thanks for your post.<BR/><BR/>We gave up trying to mirror with LVM2 as there are some lmitations such as breaking the mirror if you want to live exend the filesystem ontop of your mirrored LV, plus all the points that are mentioned in my original post.<BR/><BR/>Our setup with DM-MP -- MD -- LVM is quite finalized and is definitely IMHO the most "production compliant" one though it can be viewed as tricky.<BR/><BR/>I'll post the detailled setup in the next few days.<BR/><BR/>We are also considering VxVM among other things.<BR/><BR/>For our clusters, as we are a large HP MCServiceGuard clustering software on HP-UX client in Europe, we have a certain experience on this product which exists also for Linux.<BR/><BR/>This will be our prefered solution.<BR/><BR/>Things will be built the same way except the fact that mdadm will be replaced by HP XDC for the mirroring part.<BR/><BR/>HP XDC is in fact based on mdadm and has the advantage of being cluster aware.<BR/><BR/>I'll have a look at IBM plans.<BR/><BR/>Brem<BR/><BR/>PS: will be your on-disk log on a mirrored device? if so, how will you manage its own log ?bbloghttps://www.blogger.com/profile/12349409386285881725noreply@blogger.comtag:blogger.com,1999:blog-9095593736735388687.post-20263713796219663812008-08-14T06:41:00.000-07:002008-08-14T06:41:00.000-07:00Hi:I was really glad to read this. We're in exact...Hi:<BR/><BR/>I was really glad to read this. We're in exactly the same stage of production as you are, and exploring the exact same issues with the exact same setup. I'm currently struggling with trying to figure out the exact format of the lvcreate --mirror command, when you use on-disk log on our test systems.<BR/><BR/>In our production systems, so far we're doing what you've done -- use mdadm mirroring.<BR/><BR/>Nevertheless, here's some other information which you may find helpful:<BR/><BR/>First, you *can* address logical volumes in a more sane and reasonable by using the format "vg_name/lv_name". For instance, something like this:<BR/><BR/> lvdisplay vg_system/lv_root<BR/><BR/>Second, on intel platforms, you can consider using Veritas Volume Manager to provide extremely high quality cluster compliant volume management. It also (obviously) integrates well with Veritas Cluster Services. IMHO these two products are among the best in their class of anything I've seen.<BR/><BR/>The drawbacks: Veritas ships this product as binary only kernel modules - this means that your redhat / suse / etc support will be limited, and that you are limited in the ability to update your kernel to only what Veritas runs on. It's also not a cheap product.<BR/><BR/>Third: IBM is working on a package of very high quality mirroring software enhancements to the stock linux kernel. A Dr. Holgar Smolinski out of Germany is the primary author. At my first glance, it appears to be on the same order of functionality as Veritas. Also, IBM is willing to sell you a redhat linux support policy that includes both this package and the rest of linux, as well.<BR/><BR/>Drawbacks: It's not yet in the kernel (although Holgar is trying to push it in, but there's no schedule for getting something like this in). This is still a special order product with IBM. And most severe drawback: it doesn't yet work with Cluster LVM on linux. This means no active/active shared filesystem clusters, although you could set your cluster manager to specifically deactivate and activate volume groups on a active/passive style HA cluster.<BR/><BR/>Please let me know if you find out anything else.<BR/><BR/>-- PatAnonymoushttps://www.blogger.com/profile/09219025727205603666noreply@blogger.comtag:blogger.com,1999:blog-9095593736735388687.post-10127993866524544872008-08-03T06:04:00.000-07:002008-08-03T06:04:00.000-07:00Congratulation for your blog...Congratulation for your blog...Anonymousnoreply@blogger.com