On Wed, Mar 12, 2003 at 11:38:37AM +0800, Daniel Tan wrote: > hmm..i don't think i can wait that long...btw, if i am to use another spare > hardisk about the same size as the one i have for raid purposes...is it > possible?
Red Hat 8.0 does software raid quite well, out of the box. The raid setup is a little more confusing in disk druid than is non-raid (two steps, make raid 1 partitions, then make regular partitions out of pairs of them). Software raid 1 is bootable and requires no special hardware. If you put your two different drives on different IDE controllers raid 1 is even faster for reading than is a single disk. (Or are you on SCSI? 18 GB in 2003 sounds like a SCSI disk...) You do want to set up the raid software to tell you if a disk dies. Otherwise you might not notice--I once had a disk die and didn't notice until I got an automatic e-mail the next morning saying so. RH 8.0 includes mdadm that does this (among other things). I am running an older Red Hat without mdadm and so run an extremely simple homebrew cron job that compares /proc/mdstatus against a file holding the correct contents. You also want to run raid 1 for your swap partition so everything is covered for a running kernel and processes and your machine can keep running. You don't want raid 5, it is only for installations with lots of drives. Raid 5 requires fewer redundant disks than does raid 1, but that also makes it more complicated, and so slower to read and slower to write. Raid 5 is more for large data sets and works well with a system that keeps frequently used data on raid 1 and boots from raid 1, and puts the big data on raid 5. Specialized hardware for raid (frequently used for raid 5) is scary, because it can fail too, and being specialized, can be both expensive and difficult to quickly replace. Doing software raid means you can use commodity hardware which is both cheap and available. Given how big new disks are (a fast, bootable, and inexpensive 2 disk raid 0 system can give you over 200 GB of space) the point where raid 5 becomes sensible is really large these days. > main hd - 18.2gb (size indicated on rh disk druid) > 2nd hd - 18gb (size indicated from box) Your total space can only be the size of the smaller disk, and I suggest you go a ~smidge~ (1 MB?) smaller on each partition than that in case you have to replace a drive and, though the replacement might be nominally the same size as your surviving drive, it might have a different geometry and work out to be a bit smaller. Then again, 18 GB drives are getting kind of old (for IDE), if you lose one you will be buying used or getting something bigger. > where can i find out more info on using raid? The Red Hat 8.0 manuals will help you do the basic setup, but are spotty past that. The Raid Howto is a good start, but badly out of date. Google is always a good resource: <http://www.google.com/linux?hl=en&lr=&ie=ISO-8859-1&q=software+raid+8.0>. Also, try "man mdadm", see what it says, explore the stuff mentioned in the "See Also" section, explore some more. Do a "man raidtab" and do the same there. Good luck, -kb -- redhat-list mailing list unsubscribe mailto:[EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
