Raid 1 is simply giving you redundancy. When, not if, it breaks, theoretically both shouldn't fail. I have heard of instances where masses of drives in a dc all purchased the same time began all failing, taking out clusters as more than 1 disk was dying without any hot standby, etc. LVM is giving you flexibility. I don't fully preprovision all the space on the disk, but I do give it to lvm in the form of a physical volume. I then create raid, var, var/log, usr, home, whatever at a certain size. If I outgrow one, I do an lvextend, add data, resize2fs to grow the ext partition, and done. Usually I end up only growing home, var, or my ext0 that I use for a dump of vm images and my opt directory symlinks there. Shouldn't matter as long as they're comparable, ie. both like samsung 840's. Here's what my config looks like in use: mb@hostname ~ $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 477G 0 disk ├─sda1 8:1 0 250M 0 part │ └─md127 9:127 0 249.8M 0 raid1 /boot └─sda2 8:2 0 476.7G 0 part └─md126 9:126 0 476.6G 0 raid1 └─spv0 (dm-0) 252:0 0 476.6G 0 crypt ├─hostname--vg0-root0 (dm-1) 252:1 0 3G 0 lvm / ├─hostname--vg0-swap0 (dm-2) 252:2 0 3G 0 lvm [SWAP] ├─hostname--vg0-usr0 (dm-3) 252:3 0 9G 0 lvm /usr ├─hostname--vg0-var0 (dm-4) 252:4 0 3G 0 lvm /var ├─hostname--vg0-varlog0 (dm-5) 252:5 0 1G 0 lvm /var/log ├─hostname--vg0-home0 (dm-6) 252:6 0 64G 0 lvm /home └─hostname--vg0-ext0 (dm-7) 252:7 0 128G 0 lvm /mnt/ext0 sdb 8:16 0 477G 0 disk ├─sdb1 8:17 0 250M 0 part │ └─md127 9:127 0 249.8M 0 raid1 /boot └─sdb2 8:18 0 476.7G 0 part └─md126 9:126 0 476.6G 0 raid1 └─spv0 (dm-0) 252:0 0 476.6G 0 crypt ├─hostname--vg0-root0 (dm-1) 252:1 0 3G 0 lvm / ├─hostname--vg0-swap0 (dm-2) 252:2 0 3G 0 lvm [SWAP] ├─hostname--vg0-usr0 (dm-3) 252:3 0 9G 0 lvm /usr ├─hostname--vg0-var0 (dm-4) 252:4 0 3G 0 lvm /var ├─hostname--vg0-varlog0 (dm-5) 252:5 0 1G 0 lvm /var/log ├─hostname--vg0-home0 (dm-6) 252:6 0 64G 0 lvm /home └─hostname--vg0-ext0 (dm-7) 252:7 0 128G 0 lvm /mnt/ext0 -mb On 09/04/2014 10:19 AM, Mark Phillips wrote: > Michael, > > Thanks again for your comments, they are very helpful. I have been > googling RAID1 and LVM and finding lots of good information. > > I really like your idea of a RAID1 for the two SSDs. Does it matter if > one is msata and one is not? > > I am trying to decide on the merits of using LVM with the RAID1, since > I only have 1 disk and I normally don't partition it so I don't have > to worry about running our of space until the disk is almost full. > Could you explain to me the benefit of using LVM + RAID1 for these two > drives? How would you partition the drives? My current drive has about > 420 GB of data in /home, about 9GB in /opt, and some misc stuff in > /var, all of which I need to transfer that to the new system. > > Thanks, > > Mark > > P.S. One benefit of using both LVM and RAID1 is learning something new! ;) > > > On Wed, Sep 3, 2014 at 12:33 PM, Michael Butash > wrote: > > I really never hit any io constraints on disks honestly since > using ssd's. I watch gkrellm like a hawk and tend to notice if > something is amiss, and disks are never it, unless one dies. I > tend to abuse my system with 32db of ram and chrome and firefox > each have seen using 10gb of ram each, nothing really ever > slamming disks. > > Some games/graphics intensive apps that use bitmap caching to /tmp > or somewhere in home I'll give a ramdisk to ease it's pain. This > works well for things like minecraft servers to ease killing my > ssd's prematurely. > > I've never honestly benchmarked my disk i/o with raid, crypto, > lvm, and a fs atop them, but honestly until I'm aggravated with a > visible bottleneck, it's doing it's job. I haven't had that in a > desktop setting since going to SSD's, period. > > I'm pretty happy with the msata mx100 micron's in my dell laptop > so far. The fact I can have 2x 512gb ssd disks in my 12" laptop > and 16gb of ram is frigging great. > > Do yourself a favour, get a usb3 spindle disk for the bulk data > and get a smaller ssd. I used 32, then 64, then 128, then 256, > now up to 512gb disks that I don't feel I'm getting utterly > screwed having to buy 2x for resiliency. Slice your data > partitions adequately and learn to live within your means. You > quickly figure out what data you really need or don't when you > have to add space, but lvm's make that painless. At home I just > do this with a nas direct, but I rsync a lot of stuff against that > for backups and working between laptop/desktop on the road or not. > > My worst offenders are email, everyone else's data I carry about > (hoards of data and docs from customers), stupid windoze xp vm as > my visio runtime, and a few games if they go local. I'm fairly > glad being a linux zealot I was weaned off pc games by mid 2000's, > seeing some actually want a few hundred gigs of space these days. > Same reason I don't use win7, they have the audacity to ask for > 25gb for a base install, just so I can run visio somewhere. Not > when I have a 64gb drive. and xp is fine as a hypervisor for visio > in seamless vbox mode. > > Enter lucidchart, it's actually a decent replacement for visio > now. Then I'm finally free of any real need for windoze at all. > > -mb > > > > On 09/03/2014 10:20 AM, Mark Phillips wrote: > > > Michael, > > Great info...Thanks! > > Are there any performance (or other issues) between a > raid1with two 1tb msata ssds and rsync between one 1tb msata > ssd and 7200 rpm 1tb hdd? I like the idea of raid1 with two > ssds, but not sure if I am ready to buy 2 1tb ssds. And yes, I > really need a 1 tb drive.....Just consider me a hoarder of > data...;) > > Mark > > > --------------------------------------------------- > PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org > > To subscribe, unsubscribe, or to change your mail settings: > http://lists.phxlinux.org/mailman/listinfo/plug-discuss > >