Seagate ST34572WC Spezifikationen PDF herunterladen (Seite 4)

1. Preparing for Disk Recovery

Forewarned is forearmed. Knowing that hard disks will fail eventually, you can take some precautionary measures

to minimize your downtime, maximize your data availability, and simplify the recovery process. Consider the

following guidelines before you experience a disk failure.

Defining a Recovery Strategy

As you create logical volumes, choose one of the following recovery strategies. Each choice strikes a balance

between cost, data availability, and speed of data recovery.

1. Mirroring: If you mirror a logical volume on a separate disk, the mirror copy is online and available

while recovering from a disk failure. With hot-swappable disks, users will have no indication that a disk

was lost.

2. Restoring from backup: If you choose not to mirror, make sure you have a consistent backup plan for

any important logical volumes. The tradeoff is that you will need fewer disks, but you will lose time while

you restore data from backup media, and you will lose any data changed since your last backup.

3. Initializing from scratch: If you do not mirror or back up a logical volume, be aware that you will

lose data if the underlying hard disk fails. This can be acceptable in some cases, such as a temporary or

scratch volume.

Using Hot-Swappable Disks

The hot-swap feature implies the ability to remove or add an inactive hard disk drive module to a system while

power is still on and the SCSI bus is still active. In other words, you can replace or remove a hot-swappable disk

from a system without turning off the power to the entire system.

Consult your system hardware manuals for information about which disks in your system are hot-swappable.

Specifications for other hard disks are available in their installation manuals at

http://docs.hp.com.

Installing the Patches that Enable LVM Online Disk Replacement

LVM online disk replacement (LVM OLR) simplifies the replacement of disks under LVM. With LVM OLR, you can

temporarily disable LVM use of a disk in an active volume group. Without it, you cannot keep LVM from accessing

a disk unless you deactivate the volume group or remove the logical volumes on the disk.

LVM OLR is delivered in two patches, one patch for the kernel and one patch for the pvchange command. The

patches introduce a new option, –a, to pvchange. The –a option disables or re-enables a specified path to an

LVM disk. For more information on LVM OLR, refer to the white paper

LVM Online Disk Replacement (LVM OLR).

Both command and kernel components are required to enable LVM OLR:

• For HP-UX 11i version 1, install patches PHKL_31216 and PHCO_30698 or their superseding patches.

• For HP-UX 11i version 2, install patches PHKL_32095 and PHCO_31709 or their superseding patches.

Mirroring Critical Information, Especially the Root Volume Group

By using mirror copies of the root, boot, and primary swap logical volumes on another disk, you can use the

copies to keep your system in operation if any of these logical volumes fail.

Mirroring requires the add-on product HP MirrorDisk/UX (B5403BA). This is an extra-cost product available on the

HP-UX 11i application release media. Use the swlist command to confirm that you have HP MirrorDisk/UX

installed. For example:

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Seagate ST34572WC Spezifikationen Seite 4