6.8 Expanding the Cache Area by Adding Virtual Disks

You can expand the cache area dynamically by adding virtual disks to the virtual appliance.

Note

The following procedure uses VMware vSphere, or Hyper-V as an example.
For KVM, change "/dev/sdX" to "/dev/vdX".
For Amazon EC2, change "/dev/sdX" to "/dev/xvdX".
In Microsoft Azure, "/dev/sdaX" and "/dev/sdbX" represent the virtual disks for the system area. The virtual disks for any additional cache area start from "/dev/sdd".
To link with the cloud backup script of ETERNUS SF AdvancedCopy Manager, adding the backup volume of AdvancedCopy Manager while the cache area is expanded is not recommended. This is because if the virtual disk for expanding the cache area and the backup volume of AdvancedCopy Manager have the same capacity, the two are indistinguishable.

Add virtual disks to the virtual appliance.
You can add up to 31 virtual disks.
For virtual disk requirements, refer to "A.1 Virtual Appliance Specifications".
For more information about how to add virtual disks, refer to the documentation for your server virtualization software and cloud services.

Expand the cache storage pool.

Verify that the added virtual disk is recognized by executing the following command.

The following example shows how to add a 200 GB virtual disk.
The disk is recognized as "/dev/sdc".

# csgadm storagepool diskscan
  /dev/sda1 [     953.00 MiB]
  /dev/sda2 [      27.94 GiB]
  /dev/sda3 [      27.94 GiB]
  /dev/sda5 [      27.94 GiB]
  /dev/sda6 [       3.72 GiB]
  /dev/sdb  [     100.00 GiB] LVM physical volume
  /dev/sdc  [     200.00 GiB]
  1 disk
  5 partitions
  1 LVM physical volume whole disk
  0 LVM physical volumes

Add a virtual disk to the cache storage pool by executing the following command.
If you are adding more than one virtual disk, execute the command for each virtual disk.
```
# csgadm storagepool extend -disk /dev/sdc
```

Verify that the virtual disk has been added to the cache storage pool by executing the following command.

# csgadm storagepool show
  PV         VG             Fmt  Attr PSize      PFree
  /dev/sdb   CsgStoragePool lvm2 a--  102396.00m 102396.00m
  /dev/sdc   CsgStoragePool lvm2 a--  204796.00m 204796.00m

  VG             #PV #LV #SN Attr   VSize      VFree
  CsgStoragePool   2   0   0 wz--n- 307192.00m 307192.00m

Change the cache capacity.
For information on how to change the settings, refer to "5.2 Changing Datastore Settings".