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symbiat n00b
Joined: 20 Aug 2003 Posts: 36 Location: New York
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Posted: Tue Oct 07, 2003 9:47 pm Post subject: Software RAID, LVM and devfs in Gentoo |
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Im new to Gentoo (coming from a RedHat and Debian background but wanting the ease of FreeBSD's ports and was wondering how does one go about setting up software RAID in Gentoo for the boot and root drives? Ive worked my way through the install docs but it doesn't mention software RAID setup. Also, was wondering how I go about getting LVM going in Gentoo? Would be nice to combine software RAID with LVM for certain file systems.
My other questions is about devfs: does Gentoo use devfs by default now? Or does this require some setup?
Im glad to be moving into Gentoo - thank you in advance for any help / pointers. |
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ciaranm Retired Dev
Joined: 19 Jul 2003 Posts: 1719 Location: In Hiding
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Posted: Tue Oct 07, 2003 10:05 pm Post subject: |
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You don't usually need to do software RAID+LVM, since LVM can do striping itself. LVM's easy, anyway... The livecd kernel supports it, so just do vgscan to get started, make your PVs with pvcreate, then one or more VGs with vgcreate, then create logical volumes as you need them (lvcreate).
http://www.gentoo.org/doc/en/lvm.xml <-- start there
And yes, devfs is the default. Make sure you enable it in your kernel (ditto for LVM), or stuff breaks. |
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symbiat n00b
Joined: 20 Aug 2003 Posts: 36 Location: New York
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Posted: Tue Oct 07, 2003 10:41 pm Post subject: |
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OK, that makes sense.
What if I wanted to do /boot and / with software RAID and /var as an LVM? Or are you saying I should stick with LVM? |
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ciaranm Retired Dev
Joined: 19 Jul 2003 Posts: 1719 Location: In Hiding
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Posted: Tue Oct 07, 2003 10:51 pm Post subject: |
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Having a non-regular / and /boot will lead to much pain. You could do it, but it's probably not worth it... You wouldn't gain much performance-wise by doing that either... |
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labrador Guru
Joined: 04 Oct 2003 Posts: 316
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Posted: Wed Oct 08, 2003 4:45 pm Post subject: Does LVM provide for mirroring? |
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I'm interested in a set up that allows my system to keep running
if one drive fails. I consider a system that is lost due to a single drive
failure to be a "pain". I don't care about the small performance loss.
Does LVM provide a way to mirror even the boot partitions?
RAID 1 on /boot runs fine on my older Redhat, so I don't see why
it would a problem on shiny new gentoo. |
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ciaranm Retired Dev
Joined: 19 Jul 2003 Posts: 1719 Location: In Hiding
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Posted: Wed Oct 08, 2003 5:38 pm Post subject: Re: Does LVM provide for mirroring? |
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labrador wrote: | I'm interested in a set up that allows my system to keep running
if one drive fails. I consider a system that is lost due to a single drive
failure to be a "pain". I don't care about the small performance loss.
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Well, if you go with HW raid0, you actually get a performance gain. On reads, anyway, writes will still be the same.
Quote: |
Does LVM provide a way to mirror even the boot partitions?
RAID 1 on /boot runs fine on my older Redhat, so I don't see why
it would a problem on shiny new gentoo. |
For mirroring you need to run LVM on top of MD or HW raid. The usual rules about /boot on MD apply (yes, it's possible). |
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symbiat n00b
Joined: 20 Aug 2003 Posts: 36 Location: New York
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Posted: Wed Oct 08, 2003 6:03 pm Post subject: Re: Does LVM provide for mirroring? |
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Quote: | For mirroring you need to run LVM on top of MD or HW raid. The usual rules about /boot on MD apply (yes, it's possible). |
I have used software RAID (i.e. md) successfully on RedHat boxes. When one of the drives
failed, the machine continued running (in "degraded" mode). So, using md for / and /boot is highly desireable on some servers. (In my case, I have multiple U160 SCSI drives on a dual-Athlon box with 1Gb RAM |
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