On Thu, 19 Sep 2002, Ali Zaidi wrote:
> ================================================================
>
> Device Boot Start End Blocks Id System
> /dev/hda1 * 1 1020 8193118+ 83 Linux
> /dev/hda2 1021 2491 11815807+ 5 Extended
> /dev/hda5 1021 1148 1028128+ 82 Linux swap
> /dev/hda6 1149 1187 313236 8e Linux LVM
> /dev/hda7 1188 1200 104391 8e Linux LVM
> /dev/hda8 1201 1213 104391 8e Linux LVM
> /dev/hda9 1214 1226 104391 8e Linux LVM
> /dev/hda10 1227 1239 104391 8e Linux LVM
> /dev/hda11 1240 1241 16033+ 8e Linux LVM
> /dev/hda12 1242 1254 104391 8e Linux LVM
> /dev/hda13 1255 1267 104391 8e Linux LVM
> /dev/hda14 1268 1280 104391 8e Linux LVM
> /dev/hda15 1281 1293 104391 8e Linux LVM
> /dev/hda16 1294 2491 9622903+ 8e Linux LVM
> ================================================================
>
Errr ummm..... yes your right you are new to LVM!!! There is NO point at
all in doing this... yes I know you want "raw" devices oracle... but let
me explain.... A raw device for oracle is simply a device without a
filesystem on it.
Let me now pose you a question, if you had a "raid" device would you
define your partitions on the physical disk or on the special device after
it has been "raided"? The answer of course is after!
Think of LVM is a partion table on steriods. What your doing about is
stupid because...
1) You will create a pv volume on each one of those partions. You will
then put them all in the same volume group (lvm will effectly join them
all back together again) Then you will then reallocate the disk back into
chunks for the raw devices to be used by oracle. However if lvm spits it
differently to you then your disk will be slower not faster!
2) You want a seperate volume group for each logical volume why are you
using lvm?
Ok lets me show you the config for my "simple" system
first the partition table....
/dev/discs/disc0/part1 1 392 3148708+ b Win95 FAT32
/dev/discs/disc0/part2 * 393 441 393592+ 83 Linux
/dev/discs/disc0/part3 442 490 393592+ 83 Linux
/dev/discs/disc0/part4 491 2103 12956422+ f Win95 Ext'd
(LBA)
/dev/discs/disc0/part5 491 1003 4120641 b Win95 FAT32
/dev/discs/disc0/part6 1004 2103 8835718+ 8e Linux LVM
in linux only partions 2 and 6 are normally used.
bash# pvscan
pvscan -- reading all physical volumes (this may take a while...)
pvscan -- ACTIVE PV "/dev/ide/host0/bus0/target0/lun0/part6" of VG
"hex_vg" [8.38 GB / 0 free]
pvscan -- total: 1 [8.43 GB] / in use: 1 [8.43 GB] / in no VG: 0 [0]
Note one pv which contains the hex_vg in it....
But Hay! I want more than one partion for my system....... read on...
bash# df -k
Filesystem 1k-blocks Used Available Use% Mounted on
/dev/root 381121 71333 290109 20% /
/dev/shm 262144 4 262140 1% /tmp
/dev/hex_vg/var_lv 262132 43780 218352 17% /var
/dev/hex_vg/usr_lv 3145628 2076264 1069364 67% /usr
/dev/hex_vg/hecate1_lv
4980580 168364 4812216 4% /hecate1
ls /dev/hex_vg/
group hecate1_lv swap_lv usr_lv var_lv
Rather than using those for filesystems I could have used them for raw
devices for oracle or anything else!
This will show you how lvm has layout out the disk...
vgdisplay hex_vg
--- Volume group ---
VG Name hex_vg
VG Access read/write
VG Status available/resizable
VG # 0
MAX LV 255
Cur LV 4
Open LV 4
MAX LV Size 2 TB
Max PV 255
Cur PV 1
Act PV 1
VG Size 8.38 GB
PE Size 32 MB
Total PE 268
Alloc PE / Size 268 / 8.38 GB
Free PE / Size 0 / 0
VG UUID 5B7ut8-3kgO-F3aT-Z6QS-odhu-tYLa-wTPTKN
--- Logical volume ---
LV Name /dev/hex_vg/var_lv
VG Name hex_vg
LV Write Access read/write
LV Status available
LV # 1
# open 1
LV Size 256 MB
Current LE 8
Allocated LE 8
Allocation next free
Read ahead sectors 120
Block device 58:0
--- Logical volume ---
LV Name /dev/hex_vg/swap_lv
VG Name hex_vg
LV Write Access read/write
LV Status available
LV # 2
# open 1
LV Size 384 MB
Current LE 12
Allocated LE 12
Allocation next free
Read ahead sectors 120
Block device 58:1
--- Logical volume ---
LV Name /dev/hex_vg/usr_lv
VG Name hex_vg
LV Write Access read/write
LV Status available
LV # 3
# open 1
LV Size 3 GB
Current LE 96
Allocated LE 96
Allocation next free
Read ahead sectors 120
Block device 58:2
--- Logical volume ---
LV Name /dev/hex_vg/hecate1_lv
VG Name hex_vg
LV Write Access read/write
LV Status available
LV # 4
# open 1
LV Size 4.75 GB
Current LE 152
Allocated LE 152
Allocation next free
Read ahead sectors 120
Block device 58:3
--- Physical volumes ---
PV Name (#) /dev/ide/host0/bus0/target0/lun0/part6 (1)
PV Status available / allocatable
Total PE / Free PE 268 / 0
As you can see lvm is being my partion table for me for those partions, it
has the added bonus that because it is in an extend partion on the real
disk its position in that table could (in theory move). However I don;t
have to worry about that cos lvm will find it and my devices will still
be where I put them
/dev/<volume groupname>/<logical volume name>
James
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