Gentoo Archives: gentoo-user

From: Alan McKinnon <alan.mckinnon@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] LVM (Was: the best filesystem for server: XFS or JFS (or?))
Date: Sat, 26 Mar 2011 21:17:05
Message-Id: 2257101.Z5VrWX5cNr@nazgul
In Reply to: Re: [gentoo-user] LVM (Was: the best filesystem for server: XFS or JFS (or?)) by "Elaine C. Sharpe"
1 On Saturday 26 March 2011 15:06:31 Elaine C. Sharpe wrote:
2 > > Just because something works for most people, doesn't mean it will for
3 > > everyone either. If you lose data, it doesn't matter. LVM just adds
4 > > one more layer of something to go wrong. Me, I don't need the extra
5 > > risk of having a system that doesn't boot and a loss of data. I'm sure
6 > > there are a lot of people that see it the way I do too. They just
7 > > don't
8 > > need the extra risk.
9 >
10 > Using the least number of layers of abstraction you can get away with is
11 > a perfectly valid criteria. What I was pointing out was that informal
12 > polls of users with a sad story to tell is not a very effective way to
13 > conduct research. People say all kinds of things that just aren't true.
14
15 There's an elephant in this room. The number of actual layers is greater than
16 just LVM plus FS. It's whatever the BIOS (or a reasonable substitute is
17 doing), plus the drive firmware, kernel driver(s) - there's more than one of
18 those - plus any RAID in use (hardware or software) and finally the file
19 system.
20
21 That's a lot of layers, a lot of code, a lot of opportunity for people to
22 reveal the extent of their lack of knowledge. I've often heard it said that
23 code like ZFS and brtfs eliminates several of these layers therefore it's
24 technically a better option. That may be true, but let me just point out that
25 whatever LVM+fs+other_stuff is doing as separate chunks of code also gets done
26 by ZFS etc. You just don't see it, and just because it's abstracted away
27 doesn't mean it's not there.
28
29 --
30 alan dot mckinnon at gmail dot com

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