LV -> LP question

[unixfreak]

How does this make sense?

mawbt101(root)# lslv -m hd6
hd6:N/A
LP PP1 PV1 PP2 PV2 PP3 PV3
0001 0002 hdisk1 0108 hdisk0
0002 0100 hdisk0 0003 hdisk1
0003 0142 hdisk0 0004 hdisk1
0004 0435 hdisk0 0005 hdisk1
0005 0110 hdisk0 0006 hdisk1
0006 0111 hdisk0 0007 hdisk1
0007 0112 hdisk0 0008 hdisk1
0008 0113 hdisk0 0009 hdisk1
0009 0114 hdisk0 0010 hdisk1
0010 0115 hdisk0 0011 hdisk1
0011 0116 hdisk0 0012 hdisk1
0012 0117 hdisk0 0013 hdisk1
0013 0118 hdisk0 0014 hdisk1
0014 0119 hdisk0 0015 hdisk1
0015 0120 hdisk0 0016 hdisk1
0016 0121 hdisk0 0017 hdisk1
0017 0122 hdisk0 0018 hdisk1
0018 0123 hdisk0 0019 hdisk1
0019 0124 hdisk0 0020 hdisk1
0020 0125 hdisk0 0021 hdisk1
0021 0126 hdisk0 0022 hdisk1
0022 0127 hdisk0 0023 hdisk1
0023 0128 hdisk0 0024 hdisk1
0024 0129 hdisk0 0025 hdisk1
0025 0130 hdisk0 0026 hdisk1
0026 0131 hdisk0 0027 hdisk1
0027 0132 hdisk0 0028 hdisk1
0028 0133 hdisk0 0029 hdisk1
0029 0030 hdisk1 0080 hdisk0
0030 0031 hdisk1 0081 hdisk0
0031 0109 hdisk0 0032 hdisk1
0032 0033 hdisk1 0434 hdisk0
mawbt101(root)# lsps -a
Page Space Physical Volume Volume Group Size %Used Active Auto Type
hd6 hdisk0 rootvg 896MB 5 yes yes lv
hd6 hdisk1 rootvg 128MB 5 yes yes lv
mawbt101(root)#

Or have I misunderstood the lsps -a output. Shouldn't it show the same amount on both disks?

Cheers

 

[Breslau]

i think it all depends on how you add the space in. how did you increase its size, assuming you've done that at some point.

could you post lsvg -l rootvg?

 

[Chapter11]

Did you increase paging space by adding more partitions via smit lvm-paging space, or did you just add them by changing the lv (not in the paging space sub-menu)?

 

[unixfreak]

Chapter11: I increased it by 'chps -s 96'

Breslau: I'll have to get back to you on that as I'm not at work at the moment.

Cheers

 

[raztaboule]

lsps -a don't show you the paging space and his mirror but the piece of the paging space on hdisk0 and the other piece on hdisk1.
perhaps hdisk0 was full when you increased hd6.

lslv -m shows the physical partitions where each logical partitions of the lv is stored.
two copies of hd6 ==> lslv -m shows two pp for each lv.

 

[unixfreak]

Yes but each LP has it's copies on seperate PPs so I don't understand how it can have different sizes on the two PVs?

Cheers

 

[raztaboule]

The mistake is that you are trying to compare two differents things.

lsps -a doesn't show nothing about mirrors. just that you have 1024M of paging , 128M of this 1024 are on hdisk1 and 896M are on hdisk0. that's logical view.

Physically as the lv hd6 is mirrored you have 1024M on each disk. The 128M on hdisk1 are copied on hdisk0 and the 896M on hdisk0 are copied on hdisk1.
look at the PV1 column of lslv -m you have 4 lines with hdisk1 , that's the piece of paging of 128M.

if you had 1024M of paging on hdisk0 mirrored on hdisk1 lsps -a would show you only one line and lsps -m would gives you nearly the same output that you have now.

by the way i 'am not sure it is a good situation to have an lv splitted on two disk and mirrored on those disk. I don't know what AIX will do if ,for example in your case, hdisk0 is full and you try to increase the size of hd6 . Does it will extend the lv on hdisk1 and put a second copie on the same disk ???


hope this help.

 

[RodKnowlton]

I don't know what AIX will do if ,for example in your case, hdisk0 is full and you try to increase the size of hd6 . Does it will extend the lv on hdisk1 and put a second copie on the same disk ???

It depends on the strictness setting for the lv. The default setting is 'y', which requires that each LP copy exist on a separate physical volume, which would cause the extension to fail. If it's set to 'n', then it would work the way you described, assuming sufficient space on hdisk1.

Rod Knowlton
IBM Certified Advanced Technical Expert pSeries and AIX 5L

 

[unixfreak]

Thanks Raztaboule, that makes sense.

Yes, AIX won't per default extend with both copies on the same disk. I do have problems however, keeping it that way when moving or reorganising it.

Cheers

 

[rs6000er]

i have another question about the mirrored pagingspace(default hd6)
i mirrored my rootvg from hdisk0 to hdisk1 including default paging space - hd6.
but now i only can see one active paging space - hd6
who can explain that situation? i wonder if i should active anther one?
#lslv -l hd6
hd6:N/A
PV COPIES IN BAND DISTRIBUTION
hdisk0 163:000:000 56% 000:092:071:000:000
hdisk1 163:000:000 45% 007:074:082:000:000
lsps -a
Page Space Physical Volume Volume Group Size %Used Active Auto Type
hd6 hdisk0 rootvg 10432MB 36 yes yes lv