On Sat, Sep 01, 2007 at 09:31:03PM -0400, Douglas A. Tutty wrote: > On Sun, Sep 02, 2007 at 08:44:21AM +1000, Alex Samad wrote: > > On Sat, Sep 01, 2007 at 09:48:38AM -0400, Douglas A. Tutty wrote: > > > On Sat, Sep 01, 2007 at 12:16:00PM +1000, Alex Samad wrote: > > > > raid 1 / raid 1 /boot raid 5 - pv > > > > > > > > I have been looking at why not to raid 5 and I would go to raid 10 > > > > but I can only put 3 drives in my machine. > > > > > > > > Currently have 3x250G and am looking at getting 3x500G, if I go to > > > > mdadm raid1, then I have 500G safe 500G unsafe which is not really > > > > what I want. > > > > > 1 big vgroup and lots of lv's some with mirrors and some without ? > > > > > > I don't see a mirror option in Etch's LV create. > > > > Okay I have lenny but I thought mirroring had been in for a while, > > from my man lvcreate > > > > -m, --mirrors Mirrors > > > > I haven't looked at this previously so I might be wrong. > > Before Etch came out, when I knew that its installer would be doing LVM, > I decided that when I moved from Sarge that I'd go with LVM. On Sarge's > lvcreate, there was a -m --mirrors option. When Etch came out it wasn't > there. I haven't looked into why not but its not there. To me, its the > one big thing missing from LMV. I suppose though that if we all start > mirroring in LVM instead of setting up md, then we'll need an LV version > of mdadm to email us when a mirror degrades from a failing drive.
This is part of no having played with it, was hoping there would have been a few people who are using it to provide some feedback - yeah its good, nope its bad. Or even some people to say dm-mirror is not as good/fast as mdadm.. Guess when I get my new drives I am going to have to try it. My problem is the upgrade path, I don't have the space to backup somewhere else and reload on fresh disk....... > > > > > > > > > Here's how I would do it: > > > > > > Partition 1: 3-way raid1 64 MB for /boot > > > > I usually go for 500M, leaves me lots of room to leave stuff not sure > > why 3 way though, the spare space on the 3rd drive if i go 2 way i use > > for tmp or swap or ... > > > > If you don't have swap protected, then a failed drive could crash the > system. Put the swap on LVM. You could also put / on LVM but I didn't > suggest that since you seemed to want to keep it to a non-LV. true > > I have two drives, 70 GB each. 3 partitions: md0 for /boot, md1 raid1 > for LVM VG-mirror for the system stuff and then the two third partitions > for VG-cat for non-mirror protected stuff. /home is on a regular LV, > /var/tmp is on a striped LV. /tmp is on tmpfs. I'm running amd64 and > have a 300 M LV for / with ext3 gives 291 MB total and I have 170 MB > used with 107 free with two kernels and their modules installed. > > I suggested that you go with 3-way raid1 since you have three huge > drives anyway, you wouldn't miss 300 MB. Since its a small box with > three drives in it, cooling is tight. I would guess that you may have > an increased risk of drive failure because of it. With 3-way raid1 for > /boot and either three-way raid1 or a mirrord LV if told to mirror to > all three drives, your whole system is protected from one drive failure > and your / and /boot are protected from two drive failures. > > > > Partition 2: 3-way raid1 300 MB for / > > again not sure why the 3 way, currently i give 10G for this > > 300 MB for / is pleanty if you put all the usual mount points on > mirrored LVs. > > > nice idea to break up into little pv > > > > > > Of course, performance won't be as good as if you had 4 drives so > > > that you didn't have more than one busy md per drive, but this is a > > > good compromise. > > > > > > Why is it that you can't fit in a 4th drive? Are there only 3 bays? > > > its a shuttle case, it only has bays for 2 hard drives, I suppose I > > How do you fit in three drives plus a DVD then? the shuttle version i have has room for 3 internal + 1 dvd, I was saying 1 could remove the dvd and install another drive, but i use the dvd too much > > > could remove the dvd drive, but I use it a lot, so 3 is the magic > > number, and it worked well for me, whilst I was a raid 5 guy, but it I > > am thinking more back to raid1, but I would like to make the decision > > to mirror or not at lvcreate time not underneath > > > > been playing with some HP eva's and I like being able to set the raid > > level at the lun level > > > > > > > What about an external bay that operates at SATA speeds; look at > > > addonics. i work has a much bigger budget than mine, i was look at 500G samsungs drives for $110 (AUS$), which was a good deal > > Doug. > > > -- > To UNSUBSCRIBE, email to [EMAIL PROTECTED] > with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED] > >
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