LVM on top of Software Raid
I have frequently read that it is possible to use lvm on top of software raid multiple devices. However, the descriptions of the process were either somewhat vague or clearly related to the old software raid subsystem without persistent superblocks. I have already sent mails to the authors of the various howtos I found, but to no avail. Maybe some kind soul on this mailing list can answer my questions.
Is it possible to use multiple devices as physical volumes? The problem here seems to be related to the "partition ID" of the multiple devices. If it is possible, how do I do it? If it is not, are there any plans to fix it?
Regards
Michael Burschik
Quoted 1 line
Is it possible to use multiple devices as physical volumes?
Yes.
haverhill:~: sed 's/ / /' < /proc/lvm/global
LVM driver version 0.9.1_beta4 (09/02/2001)
Total: 6 VGs 14 PVs 13 LVs (13 LVs open 13 times)
Global: 151053 bytes malloced IOP version: 10 2 days 20:57:47 active
VG: vg01 [3 PV, 3 LV/3 open] PE Size: 4096 KB
Usage [KB/PE]: 3145728 /768 total 2527232 /617 used 618496 /151 free
PVs: [AA] md8 1048576 /256 741376 /181 307200 /75
[AA] md7 1048576 /256 737280 /180 311296 /76
[AA] md6 1048576 /256 1048576 /256 0 /0
LVs: [AWDL ] repl 409600 /100 1x open
[AWDL ] scratch 2015232 /492 1x open
[AWDL ] tmp 102400 /25 1x openVG: vg02 [1 PV, 2 LV/2 open] PE Size: 4096 KB
Usage [KB/PE]: 3997696 /976 total 3354624 /819 used 643072 /157 free
PV: [AA] md81 3997696 /976 3354624 /819 643072 /157
LVs: [AWDL ] grp3 2199552 /537 1x open [AWDL ] ligrp8 1155072 /282 1x open
VG: vg06 [4 PV, 2 LV/2 open] PE Size: 4096 KB
Usage [KB/PE]: 15990784 /3904 total 15691776 /3831 used 299008 /73 free
PVs: [AA] md82 3997696 /976 3997696 /976 0 /0
[AA] md83 3997696 /976 3997696 /976 0 /0
[AA] md85 3997696 /976 3997696 /976 0 /0
[AA] md86 3997696 /976 3698688 /903 299008 /73
LVs: [AWDL ] bigdisc 15167488 /3703 1x open[AWDL ] bigtmp 524288 /128 1x open
VG: vg04 [1 PV, 1 LV/1 open] PE Size: 4096 KB
Usage [KB/PE]: 3997696 /976 total 3080192 /752 used 917504 /224 free
PV: [AA] md101 3997696 /976 3080192 /752 917504 /224
LV: [AWDL ] var-log 3080192 /752 1x open
VG: vg08 [1 PV, 1 LV/1 open] PE Size: 4096 KB
Usage [KB/PE]: 3997696 /976 total 1048576 /256 used 2949120 /720 free
PV: [AA] md102 3997696 /976 1048576 /256 2949120 /720
LV: [AWDL ] ligrp9 1048576 /256 1x open
VG: vg10 [4 PV, 4 LV/4 open] PE Size: 4096 KB
Usage [KB/PE]: 15990784 /3904 total 5410816 /1321 used 10579968 /2583 free
PVs: [AA] md103 3997696 /976 2265088 /553 1732608 /423
[AA] md105 3997696 /976 3145728 /768 851968 /208
[AA] md106 3997696 /976 0 /0 3997696 /976
[AA] md107 3997696 /976 0 /0 3997696 /976
LVs: [AWDL ] grp2 1048576 /256 1x open
[AWDL ] grp11 446464 /109 1x open
[AWDL ] grp16 770048 /188 1x open
[AWDL ] grp17 3145728 /768 1x openhaverhill:~:
Quoted 2 lines
The problem here seems to be related to the "partition ID" of the multiple devices. If it is possible, how do I do it?
As I understand it, the check is
partition ID is not anything other than 0x8e
meaning that `partition has no ID' is OK.
Quoted 1 line · Michael Burschik
Is it possible to use multiple devices as physical volumes? The problem here seems to be related to the "partition ID" of the multiple devices. If it is possible, how do I do it? If it is not, are there any plans to fix it?
it is possible,
there is no partition id issue, you are most probably using outdated tools. just grab the latest lvm_tools from www.sistina.com
mkraid your md device, pvcreate it and you are done.
Note: if md=raid5 you must be careful that every filesystem on it must have the same blocksize.
L.
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