# Should I upgrade to kernel 2.6? LVM2?

## jimcooncat.

Seems like I just got this box working (well about two months ago) and now I'm curious about using the 2.6 kernel. 

I have an old IBM Aptiva (AMD K6-2) being used primarily as a qmail server, and soon to be running postgresql.

I'm going to start making a second (old Celeron) box as a fallback clone. I'd like to nail down my configuration, as I want to move my focus to software rather than monkeying with hardware and OS's.

I'm going to be using an LVM snapshot backup scheme and move stored email from user's MSOutlook .pst files to a more centrally managed maildirs using IMAP.

I've seen good comments on using the 2.6 kernel, but would it gain me anything worthwhile?? I don't care about very small gains in throughput or whatever.

And if I made such a move, am I forced to upgrade to LVM2? Is this also worthwhile? Could I move to LVM2 before trying out the 2.6 kernel?

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## Darth Void

Kernel 2.6 seems to be more responsive on my machine.  The ALSA drivers run in full duplex mode while the 2.4 OSS drivers ran half-duplex.  For me 2.6 is better.

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## ett_gramse_nap

 *Darth Void wrote:*   

> Kernel 2.6 seems to be more responsive on my machine.  The ALSA drivers run in full duplex mode while the 2.4 OSS drivers ran half-duplex.  For me 2.6 is better.

 

I'd say sound performance has pretty low priority on a mail server...   :Twisted Evil: 

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## jimcooncat.

I had heard that there's better scheduling, and Darth Void's better sound performance could be an indication of that.

I'm thinking that perhaps IMP, Apache2, PHP, and Courier-IMAP might be more responsive while Getmail, qmail, qmail-scanner, SpamAssassin, and clamav are chugging along in the background.

Maybe I'm expecting too much out of this machine? I popped in some RAM today, now up to 160 MB, bound to make a big difference in performance.

Experienced my first "kernel panic" today when I put the wrong cables on the hd and cd-rom. What impressed me was how far it booted before it gave me this message! Nothin' rocks like Gentoo.

Anyway, I used the gs-sources when I built this puppy from stage 1. Once I learned about LVM, I rebuilt the whole thing from scratch (made a goof in the first install anyway). Gonna put in a big second hd to store our mail, and use the LVM snapshots to produce backups from.

Been working with computers since '85, and dabbled with QNX and other oddball stuff, but I've never had this much control before. I know I'm getting to be an old fart, but I'm an impressed old fart!

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## blscreen

Keep in mind that the device-mapper snapshot and mirror target is still not implemented in the vanilla-2.6 tree. Without the development patches from http://people.sistina.com/~thornber/dm/ which I havn't tried yet, you cannot use snapshots or pvmove with kernel 2.6. In case you are using ext2/3 on your server: lvm2 still has no support for the e2fsadm script, which simplified the process of reducing a logical volume. This is no big problem, since it can be done manually with a few calculations.

I'm running 2.6 with lvm2 without problems (never had lvm1), and I'm keeping a rescue cd with kernel 2.4.22 for things like pvmove.

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## jimcooncat.

Thanks, blscreen! I think I'll wait for awhile for the snapshots to be fixed -- that's the only reason I want to have LVM anyway.

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## Moriah

I am converting from rh9 to gentoo, and upgrading to the 2.6 kernel at the same time.  I am doing nightly backups via rsync right now, but I want to use lvm2 snapshots to get a better "freeze" of the filesystem state.  Do I need to do some extra patching to make snapshots work?  I wanted to go with reiser4, but it is apparently not quite ready yet.  :-(  

I am running ext3 now, without lvm.  Maybe I should just wait another week or so for reiser4, but I *MUST* get off rh9 before the end of April when rh drops support for it!

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## Moriah

So I am using the "gentoo-dev-sources (kernel v2.6 source patched with performance-enhancing features and stability improvements)", not the vanilla 2.6; does this include lvm2 with snapshot capability, or not?

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## blscreen

It doesn't look like the device-mapper patches are included in the current gentoo-dev-sources tree. You would have to fetch them from the mentioned location and apply them manually.

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## Moriah

Looking at the page you pointed to, it shows the patches for 2.6 stable being for 2.6.0, but the gentoo-dev-sources are 2.6.3; will this present a problem?

Also, possibly off topic, is there a location to fetch patches to get reiser4 running under gentoo-dev-sources?  

I really would like to set this up right the first time, and not have to be constantly fiddling with it as updates trickle in.  I have 9 mcahines to convert from redhat, and I would like to run 2.6, lvm2, and reiser4 on all of them.  This must be finished, tested, and running smoothly, by the end of April, when redhat drops support for rh9.

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## blscreen

The stable patches are for 2.6.0 indeed. But they don't contain the mirror and  snapshot patches anyway.

Look here for the unstable 2.6.3 patches.

 *Moriah wrote:*   

> This must be finished, tested, and running smoothly, by the end of April, when redhat drops support for rh9.

 

I'm sure if you if you tell Joe Thornber, he will try even harder and have the shiny new devicemapper finished, tested and running smoothly in the stable 2.6 tree by the end of April to the benefit of us all   :Wink: 

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## Moriah

Pardon my ignorance, but I am new to Gentoo.  Who is Joe Thornber, and how do I tell him?

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## blscreen

Joe Thornber is a developer working on the devicemapper. 

In the open source community you have little more than two choices: accept the speed at which things are developing, or help to develop them. I don't think the fact that RedHat drops support can speed this process up.

My last statement was an ironic way of putting that.

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## Moriah

Without sounding presumptious, I am a fairly competent programmer.  Perhaps I could help.  I have already contributed one program that is now offered via gentoo: gemsvnc.  I would be glad to help in whatever way would be appropriate -- probably testing at this point.  I just need to find out who to hook up with to make this possible.  I will try to get in touch with Joe and see if he can use any help at this late date.

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