> We are going with a lot of Linux Guests under VM. Close to 20 per IFL and > are wondering about the experiences with the basevol/guestvol scenario. > How many People accually use this scenario? How much DASD does this really > save you? Is it worth the time and effort it takes to set this up? Could > you just setup Links to specific disks in VM for a Guest like if you just > wanted to share the binaries for say Oracle, or the /usr directory or > /home directory? Wouldn't this accomplish the same thing? What would be > the best way to go about this? It seems that you would definately save on > DASD, but how much is the Question. Does SUSE support the basevol/guestvol > out of the box, or are their some packages that need installing to make > this work? How stable is it running under this basevol/guestvol scenario? > hopefully this is not too much to ask question wise. Thanks in advance
We ran with a variation on basevol/guestvol when we were initially trying out RH 7.2. The only difference was that we had multiple guestvols per image split by mountpoint, so someone filling up /home would not impact /var (like it would have with the single-filesystem guestvol). At any rate, the DASD savings for each of your guests are as large as the basevol. There are also nice security perks, as your binaries are all RO even to root, etc, which is another layer of protection against bad things happening, accidental or otherwise. However, it was difficult to get the maintenance onto the RO devices without significant disruptions to the guests when running with the basevol/guestvol model, so when we switched to our SLES8 eval we abandoned basevol/guestvol with the intent of reconsidering it in the future. This was our first SuSE install, we weren't sure how much we'd tweak our base image, and the hoops we needed to go through to update any package on the RO basevol was a little painful. Right now we only have around 10 guests, so it's still manageable, but if the numbers start increasing then we may go back to a basevol/guestvol-type system. The initial time and effort was rather small, the real issue was the effort that went into applying any updates and keeping the rpm database current on each guest. Stability was no problem. Rather than go the basevol/guestvol extreme, I think most people doing DASD sharing just do specific mountpoints like /usr readonly. You mention /home, and you typically wouldn't have /home RO, but anything that can be RO across images (particularly filesystems that rarely need updating) can be shared. Just ensure that any minidisks linked RO are added to the linux dasd device driver ro (like with zipl.conf parameters="1000(ro),...") in addition to your fstab. This approach is more directly supported "out of the box", as the basevol/guestvol approach will require some minor customization of the SuSE startup scripts and is a bit exotic, but having a mountpoint or two like /usr RO is fairly common practice. ~ Daniel ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
