New to LVM
Looks very good, but have a few questions before setting up that disk:
1. Realttime patch kernels -- use with these, io performance hit for audio work?
2. LV for /? LV_ROOT--Ok to do this? Avoid it? OK if device mapper compiled in kernel (I do not use an initrd)?
3. Changes to /etc/fstab look straightforward. Changes to lilo.conf (yes, there are those of us who have not switched to grub)?
4. If I leave / as regular partition, how big should this be (containing /lib, /bin, /sbin, /etc, etc.)? Boot on this or separate or does it matter?
5. I will create all this on by hdd, copy everything into the fileystems from my current hdb and then move the hdd to the hdb slot. Docs say this is OK (and imply that I could even try it out booting from the old hdb /boot). True?
Quoted 4 lines · David Baron
Looks very good, but have a few questions before setting up that disk:
1. Realttime patch kernels -- use with these, io performance hit for audio work?
Straight up LVM has very little overhead once setup. Not really sure what you mean by real-time patch kernels; the requirement for LVM is to have device mapper (the dm* module(s)).
Quoted 3 lines
2. LV for /? LV_ROOT--Ok to do this? Avoid it? OK if device mapper compiled in kernel (I do not use an initrd)?
Sure! Works great. The only thing that won't work is /boot - but hopefully GRUB will fix that soon.
It's possible without initrd - you just have to link the dm* modules static in the kernel. However, it's easily setup with initrd which is the method I prefer.
Quoted 2 lines
3. Changes to
/etc/fstablook straightforward. Changes to lilo.conf (yes, there are those of us who have not switched to grub)?
LILO - man, haven't used that forever. But the boot loaders don't care. You still need a /boot that's "non-lvm". Once the kernel is loaded, there'll be device mapper support and you're go.
Quoted 2 lines
4. If I leave / as regular partition, how big should this be (containing /lib, /bin, /sbin, /etc, etc.)? Boot on this or separate or does it matter?
That's really a non-LVM question. It depends on your approach. / basically holds /etc and a few core binaries/libaries. It usually takes up less than 1GB but I would use 2G minimum. However, it really defeats the purpose of LVM? With LVM you get the flexibility to change your sizes/setup dynamically. The idea is to use as little "normal" partitions as possible to get the maximum flexibility.
Quoted 3 lines
5. I will create all this on by hdd, copy everything into the fileystems from my current hdb and then move the hdd to the hdb slot. Docs say this is OK (and imply that I could even try it out booting from the old hdb /boot). True?
Everything now a days uses UUID or similar ways to identify devices. When you format a hdd with LVM it gets assigned an UUID. This is what the "assembler" looks for - your groups are groups of UUIDs. So you can move your disks around as much as you want.
Only grub/lilo is really fixated on the BIOS address of your harddisk. Everything else shouldn't care anymore (and yes /etc/fstab should use UUIDs too).
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Regards
Peter Larsen
I'm telling you that the kernel is stable not because it's a kernel, but because I refuse to listen to arguments like this.
-- Linus Torvalds