All... Some weeks ago I circulated a request for your opinions on VxVm/VxFs/UFS/SDA etc. Thanks to everybody who replied including: Rachel Polanskis [mailto:grove@zeta.org.au] Todd M. Wilkinson [tmwilkin@mail.com] Simon-Bernard Drolet [sxi@sympatico.ca] Kevin Buterbaugh [Kevin.Buterbaugh@lifeway.com] Jeff Kennedy [jlkennedy@amcc.com] BAUMLER Julie L [julie.x.baumler@co.multnomah.or.us] Lee, Elizabeth [elizabeth.lee.contractor@fnmoc.navy.mil] King, Brooke [Brooke.King@bankofamerica.com] Karl Vogel [vogelke@dnaco.net] Broun, Bevan [brounb@adi-limited.com] EXT / STERIA TORRES Jean-Yves [ext.steria.torres@sncf.fr] John Eisenschmidt [jweisen@eisenschmidt.org] Bob Smith [b_smith44@hotmail.com] I must also thank Karl for some general tuning/performance tips. Its kinda hard to summarise actually because everybody said loads of interesting stuff. basically I have hacked in peoples comments roughly into some relevant sections below. Probably best just to read it all if you are interested and make up your own mind. Thanks everybody. best regards - T +----------------------------------------+ | TONY MILLER | Team Leader : Technical Projects, | VODAFONE LTD, | Derby House, | Newbury Business Park, | Newbury, Berkshire. | | Phone +44 (0)1635-677687(local) | Email anthony.miller@vf.vodafone.co.uk | FAX +44 (0)1635-233517 +------------------------------------------- VxVm/SDA ======== I would not have Veritas controlling my boot disks. I would be wanting to stick with something the Solaris install CD can understand. * UFS+ logging for Boot system disk * VxVM for application file systems Why ? for the first case, it's rather easy to un-mirror and un-encapsulate a UFS + logging a boot system disks and the action should be performed more often on a system disks than on application disks UFS is free and allows very fast and simple system management VxVm is application oriented and its GUI is very powerful and provides pertinent informations. Also, for application operation, for example, if I want to migrate datas from an EMCbay to another one, I can simply mirror one bay to another one with VxVm, very simply and after cut the link between the two bays. This is the easiest way and VxVm fits tho our needs Recommend using Disksuite on the boot volumes due to it's simpler recovery process. VxVm used on data volumes or where there are large numbers of disks involved. Veritas give better support for multi disk set-ups with multiple controllers as well. Disksuite is better for simple set-ups where only a few disks are involved. VxVm - don't use vxupgrade scripts as these are unreliable. Unencapsulate by hand etc and re-encapsulate/mirror after upgrade. We use VxVm everywhere - The new release of SVM in Sol9 and the patched version in the last release of Sol 8 they keep private regions on the disk rather than on a database making the use of SVM a better option in the future. We are looking at using SVM for mirroring the root disk for appliance like boxes with little system data ( DNS servers, load balanced web server etc. ). we've (I) decided that it is easier to have a standard root/boot disk set-up, so we always use SVM+UFS+logging to mirror the boot disks. On top of that, if we have more than 20 disks, or we use a cluster software or we need support 24/7, then we add VxVM+VXFS on the server. The point here is that the system disks on a simple server like a netra T1 with two disks or a SF3800 with two disks, will have the same layout. I know a lot of sites that use SVM for mirroring the OS and VxVM for everything else. That's because encapsulating the root disk is a pain compared to mirroring with SVM (especially dealing with a failed disk / OS upgrade). we've found that SVM, especially in conjunction with UFS logging, gives us an adequate level of performance. Management is simpler, since you're only dealing with one volume manager instead of two. And, as you've already noted, SVM is free while VxVM is big bucks. My answer would be this, use Solaris 9 and scratch Veritas where possible. The new volume manager in Solaris 9 looks great, does 90% of what VxVM will do, and for free. This is similar to the problems we are wrestling with. I am a huge fan of VxVM but the lack of integration into Solaris definitely causes problems. More than the upgrade issues, the fact that you have to do special work to safely install a kernel patch on a system that has a VxVM encapsulated root file system is miserable. The fact that you need 2 spare partitions to install VxVM on your root disk is also a problem for me, now that management is buying us 20-36GB root drives. Last year, I spoke with some of the Veritas engineers about the kernel patching issue and was told that in the next major release of VxVM, you wouldn't be required to have a rootdg. This would mean that you could unencapsulate root without removing VxVM, which solves both the patch and the upgrade problems. It also means that you will be able to use Disksuite for mirroring your root partitions (which is well integrated into the OS) and use VxVM for the data partitions and still be able to move your data volume groups to another system (some people work around the current situation by putting their data, not their root, in rootvg). My plan was to transition to a situation where this is our default configuration. In the meantime, I am continuing to run VxVM on all the systems that had it already. I have started using Disksuite on new systems, as long as I can meet my customer's needs. Apparently there are tools to allow you to convert SDS partitions to VxVM partitions, but this is really only an issue if you are using software RAIDS, so I haven't fully investigated it. I am by no means an expert in DiskSuite, but knowing what a volume manager can do has made it very easy for me to find the commands I need to run to meet my needs. I've been impressed with DiskSuite over the last year, and our already project/customer oriented environment has become more so in that time period; we are talking about moving to an environment where customers (projects) can choose not to pay for the cost of an extra disk to mirror their root disks (some people have already doing this against our will by going above us), but then agree to non-priority restores (i.e.. We only restore during our regular working day and if a RAIDed customer loses data, the later gets priority.); I suspect that we will start offering the choice of SDS/VxVm/both on a cost basis. We also support AIX (and therefore LVM); I find that my co-workers who are comfortable with the concepts of volume management have no problem administering multiple volume manager software, those who are confused by the concepts need a cookbook approach to most tasks, since the DiskSuite documentation provides this, adding DiskSuite to the mix hasn't been at all painful. Most of the installations where I have worked use VxVm for all file systems except the OS; those are usually Solstice Disk Suite or UFS (the logic being that the OS can be rebuilt in a relatively short time, and the VxVm volumes re-imported.) I agree that LSM does have a much more seamless way of dealing with the systems/OS disks. This message is more of a commentary than an answer to your query. One has to do one's own cost/risk/benefit analysis. A detailed answer to your questions would reveal we use SVM, VxVM, UFS, and VxFS in many situations where the other could well be used. We have tended to examine the reasons for choosing and made the decisions for classes of servers, not a blanket decision for all servers. Obviously, the smaller the support staff, the better the argument to standardise on one or the other. First, do not leave root disks encapsulated. It's a hassle. Instead follow the Sun Blueprint for best VxVM practices, and, after mirroring, reinitialise the root disk so that it is easily manageable as an ordinary VxVM disk. This doesn't make upgrading any easier, but it does make replacement easier when that unfortunate need arises. Second, I have used VxVM and SVM (SDS, ODS, whatever) for years and been pretty happy with both. However, I note that with Live Upgrade from Solaris 8 to 9 one still cannot leave the new 9 slices in SVM: they must be plain slices until one is done. However, one can access non-system slices from the Live Upgraded system. This is an advantage over VxVM because the SVM is upgraded with Solaris. Third, I have found it to be quicker and easier to replace a failed disk quickly with VxVM than with SVM. We use both Disk Suite and Volume Manager, more VM than DS. Disk Suite is a nice little product, but is limited in its application. Volume Manager is infinitely extensible, so you can add disk array after disk array to your running system and subdivide it to the Nth degree. Whichever product we're using for that particular server, we use it across the board. We do not mix Volume Manager and Disk Suite on a single system. For our production systems we use Volume Manager, mostly for the minimerge capabilities when a mirror gets out of sync. We had some troubling problems with mirror mismatches with Disk Suite, which we fine except they required a full disk remirror - not something I want to do on a production box in the middle of the day. We also have Alpha systems running OpenVMS. On those we use VMS Volume Shadowing, which is just like Disk Suite, but that's because Volume Manager isn't available for VMS, and Volume Shadowing is relatively cheap. they both have appropriate places in an enterprise. ODS/SDS is a perfectly fine choice for simple things such as mirroring and/or striping but lacks some nice bells and whistles like soft partitions and shrink online. ok, well, the newest SDS does support soft partitions but its really just a hack.... basically I use VxVM exclusively if I already need it on a machine, and I use ODS/SDS if I do not need VxVM. UFS+Logging v VxFs ================== Opinions vary here but where UFS is used ensure logging is turned on for all file systems that can support it. Always VxFS for oracle file systems because performance is so much better, and we evaluate the needs for VxFS on systems that may have high IO needs. Basically if disk performance is an issue it gets VxFS. UFS + logging hasn't proven itself to be a speedy system as of yet. VxFS is by far, a better file system in terms of proven reliability and performance. Plus it looks to work with large 500GB+ sizes much better than UFS has shown itself in the past. If you are going to spend the bucks to first purchase VxVM on a large system ( tier 3 and sometimes even tier 2 ), you probably have the need for VxFS on it as well for a least one application. So once you have a license to run VxFS on a box you might as well stick with it over UFS+logging just to keep things similar, not to mention performance. Veritas file system has really been slower than UFS since Solaris 8 came out unless you get QuickIO, then it makes up the difference and then some (but it costs money of course). Now that Solaris 9 UFS supports snapshots as well I can see no reason to use Veritas for anything except very specific application servers (like high transaction Oracle servers). Even then you may be better off with straight Solaris for the simplicity and integration. Fourth, I have had at least two occasions where I had to turn off UFS logging in order to mount a formerly logged UFS. It simply quit working. I found this odd because the UFS logging code is the same as what was in SDS at the time and may be the same as what's in SVM now. Yet, it happened. I have never had this problem with VxFS. UFS + logging. Some suggestions are below. VxFS is too expensive, and if you spread stuff over several drives and get a media problem, it's tough to find out what drive is actually failing. for most things UFS+logging is just fine but for environments with heavy loads VxFS can really extend the performance of the hardware. e.g. places like busy: databases, mail, news servers. basically anywhere with small individual or random i/o will see an improvement. Sun's new file system and volume manager (formerly developed by LSC) perform very well against VxFS for high end database needs. the down side is that the product is still fairly young, management is rough and administration/tuning can be tedious. Snapshotting capabilities of Verita =================================== Most didn't comment about this at all. The message from those that did was basically: Solaris 8 & above now also has "fssnap" provided native which will do snapshots. I was actually aware of this because we use it internally - I was interested to see how many others use it. Fifth, one can now take snapshots with UFS, but I haven't tried this feature, yet. This is one feature where VxFS used to be a clear winner because only VxFS had it, but no more. HP-UX user, do you have any intentions to migrate to VxVm ========================================================= Not many responded here. We did use VxVM on HP, but the support folks ( hp support folks ), through such a hissy fit about it that finally discontinued its use and went back to HP LVM. Recover procedures although never tested seemed a little complex on the HP side with VxVM. Please note our HP environment and VxVM on HP is very small. _______________________________________________ sunmanagers mailing list sunmanagers@sunmanagers.org http://www.sunmanagers.org/mailman/listinfo/sunmanagersReceived on Sun Aug 25 21:55:24 2002
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