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Installing Disks - general questions

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Brian Bartley
Frequent Advisor

Installing Disks - general questions

I need to add two disks to our surestore 2100 enclosure, and I don't have any disk or LVM experience. I've done the research and it looks fairly straightforward.

Server is A-class running 11.11, we have online jfs and mirrordisk products. JFS info:

swlist -l product | grep -i jfs
JFS B.11.11 The Base VxFS File System
OnlineJFS B. Online features of the VxFS File System
PHKL_24026 1.0 JFS Filesystem swap corruption
PHKL_28512 1.0 Fix for POSIX_AIO in JFS3.3
PHKL_29115 1.0 JFS Direct I/O cumulative patch
PHKL_30366 1.0 JFS3.3;ACL patch
PHKL_34805 1.0 JFS3.3 patch; mmap

the license command shows it's an active JFS license

I've read a number of forum posts on how to add disks, I understand I need to make sure the address is claimed with ioscan, then I need to use pvcreate, vgextend, lvextend, and fsadm. Also I may need to use insf if the device files don't get created automatically. The man pages for insf say to use it in single-user mode, but the other forum posts never mentioned that, they just said use insf -e, or insf -e -H . We're not adding any new VGs or LVOLs, just extending existing non-root, non-swap filesystems. I'm aware that if pvcreate fails and I need to use pvcreate -f then to be careful to hit the correct disk. I know about the max pe's per pv issue as well. I'll check with vgdisplay to see if pvcreate/vgextend succeeded in adding the disks to vg00 before using lvextend.

current internal disks:
disk 0 0/0/1/1.15.0 sdisk CLAIMED DEVICE SEAGATE ST318404LC
disk 2 0/0/2/1.15.0 sdisk CLAIMED DEVICE SEAGATE ST318404LC

current external disks in surestore cabinet:

disk 3 0/6/0/0.9.0 sdisk CLAIMED DEVICE HP 18.2GST318406LC
disk 4 0/6/0/0.11.0 sdisk CLAIMED DEVICE HP 18.2GST318406LC

the surestore manual says slots one and two will use addresses 9 and 11, which is confirmed by above ioscan output, and slots three and four will use addresses 13 and 15. The disks should arrive tomorrow, I'll check them and if there's a way to set the scsi address I'll address them appropriately. I don't know if these disks(A7329A) are addressable or if the cabinet takes care of that part. I'm assuming it's ok to use address 15 for the third(the two internals also use 15) time since it's on a different hardware path.

I'm thinking about using SAM - because it might do a better job of creating the device files - to add the disks to vg00, then use CLI after that for lvextend and fsadm. The surestore is hot-pluggable, but I think I'll take the system down to housekeeping power(halt but not power off) to insert the disks, then boot and check to see if disks are in CLAIMED state. I'm hoping this might let the system find the disks at pre-boot time and save me some insf configuration.

A couple questions for the community:

Is there a way to check to see if the new disks are recognized from the ISL prompt? I see where one can search for bootable devices, but is it possible to view the new disk info from inside ISL? Maybe I should go into single-user mode and use ioscan if I want to check the disks before booting to multi-user mode?

Although online jfs is made to work online, are there any reasons why it might be best to use fsadm in single-user mode to extend the filesystems? If the filesystem isn't mounted can I still use fsadm, or would I use extendfs?

Should I check for online jfs patches before doing fsadm, or should my version(listed above) suffice?

Also I keep seeing references to the Boot Control Handler, is that another name for the ISL prompt? If not could someone describe the difference between the two?

Finally, our /opt lvol will wind up being spread across four disks, it's already using two because it's mirrored, and when I add two more disks and extend/mirror /opt it will reside on those disks as well, and both are on the same scsi controller, which is not good because a controller failure will affect both mirrors. I know I should blow everything out and redo the LVMs properly, but I don't feel confident doing that without help, and we only need to keep the system going for another year or two. Could I run into performance or other problems extending /opt this way? Thanks for all replies,


PS - I chose the "system administration" area of the forum because I had some questions not directly disk-related.
Brian Bartley
Campus Card Services
Indiana University
Valued Contributor

Re: Installing Disks - general questions

Hello Brian,

Is there a way to check to see if the new disks are recognized from the ISL prompt?

--you want to extend /opt with a disk from san
?If SAN is not availble in some point of time, then root VG also not get activated due to quorum.
vg00 should be only for OS , however nothing will stop you from ading external disk from vg00.
Johnson Punniyalingam
Honored Contributor

Re: Installing Disks - general questions

>>Could I run into performance or other problems extending /opt this way?<<<

I d'not see much "performance issue" were if have you'r some disks of /opt file systems resides some in (internal disk) & (external disk) As long as their is no (disk bottle) has been caused due heavy I/O on disks you should be OK,

well again "External Disks" always have some better perform in prospects of (disk rpm) (controller redundancy) (RAID levels) ..etc
Problems are common to all, but attitude makes the difference
Acclaimed Contributor

Re: Installing Disks - general questions

Your existing disks:

disk 3 0/6/0/0.9.0 sdisk CLAIMED DEVICE HP 18.2GST318406LC
disk 4 0/6/0/0.11.0 sdisk CLAIMED DEVICE HP 18.2GST318406LC

expect the new disks as

disk 3 0/6/0/0.13.0

disk 3 0/6/0/0.15.0

Your couple of questions:

ISL (initial system loader) is on a disks, you cannot see other disks from there.

ISL and BCH are different.

On a cold boot, the system does the selftest, reaches BCH, boots a disks and launches ISL, then the kernel.

Hope this helps!

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those who understand binary, and those who don't.

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Brian Bartley
Frequent Advisor

Re: Installing Disks - general questions

Thanks for all replies, the disks are recognized in the system, if I have any problems extending the fs I'll post it. Thanks,

Brian Bartley
Campus Card Services
Indiana University