Maximum LUNS?

[Chris Fadrowski]

I have an HPUX 11.0 server connected to a EMC SYM. I currently have 23 LUNS assigned thur LVM (disks). I want to add another 23 LUNS. Is there a maximum amount of LUNS LVM can handle? if so, what is the max.

[Sridhar Bhaskarla]

Hi Chris,

LUNs are seen as disks. So, the restriction of the maximum number of PVs apply. Each volume group can have a maximum of 255 PVs. So, you shouldn't have any problem if you created your volume group with a non-default -p option above 46. Or you can create a seperate volume group if it works for you.

-Sri

[Thom Cornwell]

The number 23 comes to mind when you are talking about PVlinks/EMC. Are you running pvlinks, and if you are I would recommend looking into the number of PV links per VG, and how that fits into your schema.

[Chris Fadrowski]

actually to be more detailed;

1.All LUNS are 8 gig on a physical 18 gig drive.
2. I am using PV links for alternate paths.
3. each VG has it's own 2 LUNS, primary, and alternate
4. There are only 2 PV associated with all of them expect one in which i have 3 assigned.

I guess what i am asking is there a limit on how many VG's, PV's, or LV's on my system.

[Sridhar Bhaskarla · Accepted solution]

Hi Chris.

1. Max No. of PVs in a VG = 255
2. Max No. of LVs in a VG = 255
3. Max No. of VGs in a system = maxvgs kernel parameter
4. Max No. of paths to a PV = 8 (1 pri and 7 alt)

Does this help you?. Here PV = LUN.

-Sri

[Wodisch]

Hello Chris,

the way you work your limit is the kernel parameter "maxvgs", and it sdefault is 10, and hence, you'll have to increase it, perhaps vene to the theoretical limit of 255 (I have never tried that many VGs myself).

Just my $0.02,
Wodisch