How to add a disk on AIX Logical Volume Manager (LVM)

In the last post of AIX, I had explained that how we create a logical volume manager on AIX operating system. In this post, I will explain to you how to add a disk on AIX logical volume manager.

LVM (Logical Volume Manager) is a tool for logical volume management which includes allocating disks, striping, mirroring and resizing logical volumes.With LVM, a hard drive or set of hard drives is allocated to one or more physical volumes.

LVM allows users to create partitions from more than one disk and allows them to extend the filesystem size online within few seconds.

Step by step method to add a disk on LVM.

1. In the first step we will add the physical or virtual disk to the logical partition. Once the new disk is added on the logical partition then we can able to go for next step.

2. Now, rescan your system hardware so that the Operating system can find which new hard disk is add on the server. For this please use the below command to scan the hardware on AIX operating system.

aix:/> cfgmgr

3. In this step, we will check the disk. For example, let’s assume that the new disk is hdisk1, so please run the below command to check the disk.

aix:/> lsdev -Cc disk

hdisk0  Available  Virtual SCSI Disk Drive

hdisk1  Available  Virtual SCSI Disk Drive

aix:/> lspv

hdisk0      00f68f03d1e42951       rootvg          active

hdisk1      00f68f03d20beafd       vstorage        active

hdisk2      00f68f03d20ceb37       vstorage        active

if you see the above both output, you can found that hdisk1 is available to add on Voulme group.

4. In this step, now you need to create a new group and move the new disk hdisk1 in there. Let's assume the new group named is "rootvg". So please find the below command to create a new group and add the disk in it.

aix:/> mkvg -y rootvg hdisk1

5. Now you can look at the size of hdisk1. Please run the below command , you can found the below output regarding the disk space of your disk and this command would not work if it is not associated with the volume group.

aix:/> lspv hdisk1

PHYSICAL VOLUME:    hdisk1                   VOLUME GROUP:     rootvg

PV IDENTIFIER:      00f68f03d1e42951 VG IDENTIFIER     00f68f0300004c0000000153d1e429c1

PV STATE:           active

STALE PARTITIONS:   0                        ALLOCATABLE:      yes

PP SIZE:            128 megabyte(s)          LOGICAL VOLUMES:  17

TOTAL PPs:          799 (102272 megabytes)   VG DESCRIPTORS:   2

FREE PPs:           118 (15104 megabytes)    HOT SPARE:        no

USED PPs:           681 (87168 megabytes)    MAX REQUEST:      256 kilobytes

FREE DISTRIBUTION:  11..00..00..00..107

USED DISTRIBUTION:  149..160..159..160..53

MIRROR POOL:        None

6. In this step , now we will create a log logical volume for jfs2 file system and this needs to be part of vloume group "rootvg".

aix:/> mklv -t jfs2log rootvg 1

As i can not paste the my machine output as I am already add it, You can add at your end , if any issue occur on this stage please comment on the post.

7. Now, we will check the new logical volume (lv) and you can used the below command to check the new logical volume present on the AIX server.Normally on AIX server we are used "loglv00" logical name, as on my machine I used the same name.

aix:/> lsvg

rootvg

aix:/> lsvg -l rootvg

rootvg:

LV NAME             TYPE       LPs     PPs     PVs  LV STATE      MOUNT POINT

hd5                 boot       1       1       1    closed/syncd  N/A

hd6                 paging     404     404     1    open/syncd    N/A

loglv00             jfs2log    1       1       1    open/syncd    N/A

hd4                 jfs2       4       4       1    open/syncd    /

If you see the above both the output, you can find that "rootvg" is voulme group present and in rootvg, you can find the logical volume "loglv00".

8. In this, we will create a logical volume and fixed their size , lets assume we will used 30GB size and used the logical volume name lglv_test.

aix:/> lsvg rootvg

aix:/> mklv -t jfs2 -y lglv_test rootvg 30G

aix:/> mkfs -o log=/dev/loglv00 -V jfs2 /dev/lglv_test

9. In the seconf last step we will mount the newly created file system on the AIX operating system.

aix:/> mkdir /test

aix:/> mount -o log=/dev/loglv00 /dev/lglv_test /test

In this example , we will create a "/test" file system and mount the file system on this folder.

10. In the final step we will make a permament entry of this file system in "/etc/filesystems file so once you take a reboot of AIX server, file system will mount permamently, otherwise you need to mount again if you not made an entry in /etc/filesystems.

Hope this post is useful for you, as this step by step method you can not found in other sites, In case still you are facing any issue related to this topic, please comment on this post, I will revert to you with solution.

How to find the boot disk from HP-UX operating system

In this article , I would explain to you how we find which disk are used to boot the running HP-UX operating system. This is a bit tricky because its depending on the version of HP-UX, and whether it is using LVM or the less common choice.

For LVM disk layouts:

For 11.11 and earlier, use the below command to check which disk is in used.

# echo “boot_string/S” | adb -k /stand/vmunix /dev/kmem

    boot_string:

    boot_string:    disk(0/0/2/0.6.0.0.0.0.0;0)/stand/vmunix

For 11.23, there are different ways for PARISC versus IA64:

PARISC:

# echo “boot_string/S” | adb -o /stand/vmunix /dev/kmem

    boot_string:

    boot_string:    disk(1/0/0/3/0.6.0.0.0.0.0;0)/stand/vmunix

IA64 (Itanium/Integrity):

# echo “bootdev/x” | adb -n /stand/vmunix /dev/kmem

    bootdev:

        0x100001c

Now to find the actual path, you’ll have to match the 0x100001c value to a minor number in the /dev/disk directory. Compare only the last 6 digits of the number (00001c) to find the device file. Then by using lssf, you can decode the hardware path:

    # DSK=$(ll /dev/disk | awk ‘/00001c/{print $NF}’)

    # echo $DSK

    disk11_p2

    # HWPATH=$(lssf /dev/disk/$DSK | awk ‘{print $(NF-1)}’)

    # echo “$DSK path = $HWPATH”

    disk11_p2 path = 64000/0xfa00/0xa

You can also use ioscan -m dsf to map agile device file names to legacy (CTD) style.

For VxVM disk layouts:

# echo “raw_root/X” | adb -o /stand/vmunix /dev/kmem

     raw_root:

     raw_root:       0x3000002

This value is the minor number for the disk that was used to boot the current system. The minor number is found in the /dev/vx/dmp directory.

     # DSK=$(ll /dev/vx/dmp | awk ‘/000002/{print $NF}’)

     # echo $DSK

    c2t1d0s2

     # HWPATH=$(lssf /dev/dsk/$DSK | awk ‘{print $(NF-1)}’)

     # echo “$DSK path = $HWPATH”

     c2t1d0s2 path = 0/1/1/0.1.0

For completeness, I should mention that 11.31 will report the boot disk path in syslog.log (LVM or VxVM) like this:

vmunix: Boot device’s HP-UX HW path is: 0/1/1/0.0×1.0x0

However, syslog.log is a catch-all for a lot of items and often needs to be truncated when it grows too large. As a result, it can’t be relied on to always contain the current boot disk.

How to change a disk in SVM Solaris volume manager

Hope you are doing well at your end. This post documentation explain how to change a disk in SVM ( Solaris volume manager).It means that we have mirrored the disk (RAID1) using SVM. Solaris Volume manager is basically used for creating, modifying & partitioning the different RAID partition.

In this post, I will take my sparc server machine. My Sun Sparc server consist 2 hard disk, let us assume the server has 2 hard disk: c0t0d0 and c0t1d0. We will assume c0t0d0 failed and need to be replaced.

Step by Step Method as described below:

1. In the initial step, we will find that which hard disk is down or faulty. To check this we will used "format" command.

sun01# format

       0. c0t0d0 <__drive type unknown__>

          /pci@0,600000/pci@0/pci@8/pci@0/scsi@1/sd@0,0

       1. c0t1d0 <SUN146G cyl 14087 alt 2 hd 24 sec 848>

          /pci@0,600000/pci@0/pci@8/pci@0/scsi@1/sd@1,0

If you see the "format" command output, we have two disk "c0t0d0,c0t1d0". Disk "c0t0d0" is in faulty state and it's down, You can see the drive type is in unknown state.

2. If you are running the "metastat" command you can see the status of hard disk which is show status in "need maintenance".

sun01# metastat    # will show status in "need maintenance"

        flags           first blk       block count

     a        u         16              8192            /dev/dsk/c0t0d0s7

     a        u         8208            8192            /dev/dsk/c0t0d0s7

     a    p  luo        16              8192            /dev/dsk/c0t1d0s7

     a    p  luo        8208            8192            /dev/dsk/c0t1d0s7

sun01# metadb -d c0t0d0s7

sun01# metadb

Using above command we delete metadb on failing disk and check that metadb on the other disk.

4. Now, we will unconfigure the corresponding disk which is down right now. This is the main step of this post so you can more careful while running the command which is given below.

sun01# cfgadm -al

sun01# cfgadm -f -c unconfigure c0::dsk/c0t0d0

sun01# cfgadm -al

Using cfgadm command we will unconfigure the c0t0d0 faulty hard disk so that we will replace the down hard disk in next step.

5. Now you can change the faulty disk to new one and reconfigure it again with same name.

sun01# cfgadm -c configure c0::dsk/c0t0d0

sun01# cfgadm -al

6. In this steo we will duplicate partitionning schema of first disk to the second and create metadb.

sun01# prtvtoc /dev/rdsk/c0t1d0s2 | fmthard -s - /dev/rdsk/c0t0d0s2

sun01# metadb -a -f -c2 /dev/dsk/c0t0d0s7

7. In second last step you will run all the below command for replacement of the failinf SVM partition.

sun01# metastat

sun01# metareplace -ef d4 c0t0d0s4

sun01# metareplace -ef d3 c0t0d0s3

sun01# metareplace -ef d1 c0t0d0s1

sun01# metareplace -ef d0 c0t0d0s0

sun01# metareplace -ef d5 c0t0d0s5

sun01# metareplace -ef d6 c0t0d0s6

sun01# metasync d0

sun01# metasync d1

sun01# metasync d3

sun01# metasync d4

sun01# metasync d5

sun01# metasync d6

sun01# metasync d7

8. In final step you need to make the disk bootable so that operating system will be boot on the mirror disk.

sun01# installboot /usr/platform/`uname -i`/lib/fs/ufs/bootblk /dev/rdsk/c0t0d0s0

Using this step you can make a disk bootable. I hope this post is useful for you. You are requested to please comment on the post if you have any issue, I will try to back you with my answer.