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>13.3. Add a new disk to a multi-disk SCSI system</H1
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN1155"
></A
>13.3.1. Current situation</H2
><P
> A data centre machine has 6 disks attached as follows:
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><PRE
CLASS="screen"
> <B
CLASS="command"
># pvscan</B
>
<TT
CLASS="computeroutput"
>pvscan -- ACTIVE PV "/dev/sda" of VG "dev" [1.95 GB / 0 free]
pvscan -- ACTIVE PV "/dev/sdb" of VG "sales" [1.95 GB / 0 free]
pvscan -- ACTIVE PV "/dev/sdc" of VG "ops" [1.95 GB / 44 MB free]
pvscan -- ACTIVE PV "/dev/sdd" of VG "dev" [1.95 GB / 0 free]
pvscan -- ACTIVE PV "/dev/sde1" of VG "ops" [996 MB / 52 MB free]
pvscan -- ACTIVE PV "/dev/sde2" of VG "sales" [996 MB / 944 MB free]
pvscan -- ACTIVE PV "/dev/sdf1" of VG "ops" [996 MB / 0 free]
pvscan -- ACTIVE PV "/dev/sdf2" of VG "dev" [996 MB / 72 MB free]
pvscan -- total: 8 [11.72 GB] / in use: 8 [11.72 GB] / in no VG: 0 [0]</TT
>
<B
CLASS="command"
># df</B
>
<TT
CLASS="computeroutput"
>Filesystem 1k-blocks Used Available Use% Mounted on
/dev/dev/cvs 1342492 516468 757828 41% /mnt/dev/cvs
/dev/dev/users 2064208 2060036 4172 100% /mnt/dev/users
/dev/dev/build 1548144 1023041 525103 66% /mnt/dev/build
/dev/ops/databases 2890692 2302417 588275 79% /mnt/ops/databases
/dev/sales/users 2064208 871214 1192994 42% /mnt/sales/users
/dev/ops/batch 1032088 897122 134966 86% /mnt/ops/batch</TT
>
</PRE
></FONT
></TD
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>
As you can see the "dev" and "ops" groups are getting full so
a new disk is purchased and added to the system. It becomes
<TT
CLASS="filename"
>/dev/sdg</TT
>.
</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN1164"
></A
>13.3.2. Prepare the disk partitions</H2
><P
> The new disk is to be shared equally between ops and dev so
it is partitioned into two physical volumes /dev/sdg1 and
/dev/sdg2 :
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><PRE
CLASS="screen"
> <B
CLASS="command"
># fdisk /dev/sdg</B
>
<TT
CLASS="computeroutput"
> Device contains neither a valid DOS partition table, nor Sun or SGI
disklabel Building a new DOS disklabel. Changes will remain in memory
only, until you decide to write them. After that, of course, the
previous content won't be recoverable.</TT
>
<TT
CLASS="prompt"
>Command (m for help): </TT
>n
<TT
CLASS="computeroutput"
>Command action
e extended
p primary partition (1-4)</TT
>
p
<TT
CLASS="prompt"
>Partition number (1-4): </TT
>1
<TT
CLASS="prompt"
>First cylinder (1-1000, default 1):</TT
>
<TT
CLASS="computeroutput"
>Using default value 1</TT
>
<TT
CLASS="prompt"
>Last cylinder or +size or +sizeM or +sizeK (1-1000, default 1000): </TT
>500
<TT
CLASS="prompt"
>Command (m for help): </TT
>n
<TT
CLASS="computeroutput"
>Command action
e extended
p primary partition (1-4)</TT
>
p
<TT
CLASS="prompt"
>Partition number (1-4): </TT
>2
<TT
CLASS="prompt"
>First cylinder (501-1000, default 501):</TT
>
<TT
CLASS="computeroutput"
>Using default value 501</TT
>
<TT
CLASS="prompt"
>Last cylinder or +size or +sizeM or +sizeK (501-1000, default 1000):</TT
>
<TT
CLASS="computeroutput"
>Using default value 1000</TT
>
<TT
CLASS="prompt"
>Command (m for help): </TT
>t
<TT
CLASS="prompt"
>Partition number (1-4): </TT
>1
<TT
CLASS="prompt"
>Hex code (type L to list codes): </TT
>8e
<TT
CLASS="computeroutput"
>Changed system type of partition 1 to 8e (Unknown)</TT
>
<TT
CLASS="prompt"
>Command (m for help): </TT
>t
<TT
CLASS="prompt"
>Partition number (1-4): </TT
>2
<TT
CLASS="prompt"
>Hex code (type L to list codes): </TT
>8e
<TT
CLASS="computeroutput"
>Changed system type of partition 2 to 8e (Unknown)</TT
>
<TT
CLASS="prompt"
>Command (m for help): </TT
>w
<TT
CLASS="computeroutput"
>The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: If you have created or modified any DOS 6.x partitions,
please see the fdisk manual page for additional information.
</TT
>
</PRE
></FONT
></TD
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>
</P
><P
> Next physical volumes are created on this partition:
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><TD
><FONT
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><PRE
CLASS="screen"
> <B
CLASS="command"
># pvcreate /dev/sdg1</B
>
<TT
CLASS="computeroutput"
>pvcreate -- physical volume "/dev/sdg1" successfully created</TT
>
<B
CLASS="command"
># pvcreate /dev/sdg2</B
>
<TT
CLASS="computeroutput"
>pvcreate -- physical volume "/dev/sdg2" successfully created</TT
>
</PRE
></FONT
></TD
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>
</P
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><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN1199"
></A
>13.3.3. Add the new disks to the volume groups</H2
><P
> The volumes are then added to the dev and ops volume groups:
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><TD
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><PRE
CLASS="screen"
> <B
CLASS="command"
># vgextend ops /dev/sdg1</B
>
<TT
CLASS="computeroutput"
>vgextend -- INFO: maximum logical volume size is 255.99 Gigabyte
vgextend -- doing automatic backup of volume group "ops"
vgextend -- volume group "ops" successfully extended</TT
>
<B
CLASS="command"
># vgextend dev /dev/sdg2</B
>
<TT
CLASS="computeroutput"
>vgextend -- INFO: maximum logical volume size is 255.99 Gigabyte
vgextend -- doing automatic backup of volume group "dev"
vgextend -- volume group "dev" successfully extended</TT
>
<B
CLASS="command"
># pvscan</B
>
<TT
CLASS="computeroutput"
>pvscan -- reading all physical volumes (this may take a while...)
pvscan -- ACTIVE PV "/dev/sda" of VG "dev" [1.95 GB / 0 free]
pvscan -- ACTIVE PV "/dev/sdb" of VG "sales" [1.95 GB / 0 free]
pvscan -- ACTIVE PV "/dev/sdc" of VG "ops" [1.95 GB / 44 MB free]
pvscan -- ACTIVE PV "/dev/sdd" of VG "dev" [1.95 GB / 0 free]
pvscan -- ACTIVE PV "/dev/sde1" of VG "ops" [996 MB / 52 MB free]
pvscan -- ACTIVE PV "/dev/sde2" of VG "sales" [996 MB / 944 MB free]
pvscan -- ACTIVE PV "/dev/sdf1" of VG "ops" [996 MB / 0 free]
pvscan -- ACTIVE PV "/dev/sdf2" of VG "dev" [996 MB / 72 MB free]
pvscan -- ACTIVE PV "/dev/sdg1" of VG "ops" [996 MB / 996 MB free]
pvscan -- ACTIVE PV "/dev/sdg2" of VG "dev" [996 MB / 996 MB free]
pvscan -- total: 10 [13.67 GB] / in use: 10 [13.67 GB] / in no VG: 0 [0]</TT
>
</PRE
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>
</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN1209"
></A
>13.3.4. Extend the file systems</H2
><P
> The next thing to do is to extend the file systems so that the
users can make use of the extra space.
</P
><P
> There are tools to allow online-resizing of ext2 file systems
but here we take the safe route and unmount the two file systems
before resizing them:
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><PRE
CLASS="screen"
> <B
CLASS="command"
># umount /mnt/ops/batch
# umount /mnt/dev/users</B
>
</PRE
></FONT
></TD
></TR
></TABLE
>
</P
><P
> We then use the e2fsadm command to resize the logical volume and
the ext2 file system on one operation. We are using ext2resize
instead of resize2fs (which is the default command for e2fsadm)
so we define the environment variable E2FSADM_RESIZE_CMD to tell
e2fsadm to use that command.
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><TD
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><PRE
CLASS="screen"
> <B
CLASS="command"
># export E2FSADM_RESIZE_CMD=ext2resize
# e2fsadm /dev/ops/batch -L+500M</B
>
<TT
CLASS="computeroutput"
>e2fsck 1.18, 11-Nov-1999 for EXT2 FS 0.5b, 95/08/09
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/ops/batch: 11/131072 files (0.0<!-- non-contiguous), 4127/262144 blocks
lvextend -- extending logical volume "/dev/ops/batch" to 1.49 GB
lvextend -- doing automatic backup of volume group "ops"
lvextend -- logical volume "/dev/ops/batch" successfully extended
ext2resize v1.1.15 - 2000/08/08 for EXT2FS 0.5b
e2fsadm -- ext2fs in logical volume "/dev/ops/batch" successfully extended to 1.49 GB</TT
>
<B
CLASS="command"
># e2fsadm /dev/dev/users -L+900M</B
>
<TT
CLASS="computeroutput"
>e2fsck 1.18, 11-Nov-1999 for EXT2 FS 0.5b, 95/08/09
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/dev/users: 12/262144 files (0.0% non-contiguous), 275245/524288 blocks
lvextend -- extending logical volume "/dev/dev/users" to 2.88 GB
lvextend -- doing automatic backup of volume group "dev"
lvextend -- logical volume "/dev/dev/users" successfully extended
ext2resize v1.1.15 - 2000/08/08 for EXT2FS 0.5b
e2fsadm -- ext2fs in logical volume "/dev/dev/users" successfully extended to 2.88 GB</TT
>
</PRE
></FONT
></TD
></TR
></TABLE
>
</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN1221"
></A
>13.3.5. Remount the extended volumes</H2
><P
> We can now remount the file systems and see that the is plenty
of space.
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BORDER="0"
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><TD
><FONT
COLOR="#000000"
><PRE
CLASS="screen"
> <B
CLASS="command"
># mount /dev/ops/batch
# mount /dev/dev/users
# df</B
>
<TT
CLASS="computeroutput"
>Filesystem 1k-blocks Used Available Use% Mounted on
/dev/dev/cvs 1342492 516468 757828 41% /mnt/dev/cvs
/dev/dev/users 2969360 2060036 909324 69% /mnt/dev/users
/dev/dev/build 1548144 1023041 525103 66% /mnt/dev/build
/dev/ops/databases 2890692 2302417 588275 79% /mnt/ops/databases
/dev/sales/users 2064208 871214 1192994 42% /mnt/sales/users
/dev/ops/batch 1535856 897122 638734 58% /mnt/ops/batch</TT
>
</PRE
></FONT
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