HP StoreOnce Backup - Manual (Page 159)

15 Storage management
This chapter describes:
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The storage RAID configuration
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How to identify a failed disk
•
How to replace a disk
•
How to rebuild the RAID if several disks fail
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How to expand storage after adding a new shelf
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How to expand storage using a previously configured shelf
NOTE: For instructions on how to connect additional storage by adding a new capacity upgrade
enclosure (not available with the StoreOnce 2700 or 2620 Backup system), please see the printed
documentation supplied with the additional storage.
NOTE: It is not recommended to add an enclosure containing disks that already have a storage
configuration present, for example, an enclosure moved from another StoreOnce appliance. If this
is done, the previous configuration must be deleted from this enclosure before expanding the
storage.
RAID configuration
All HP StoreOnce Backup systems are supplied with their base storage already configured for use,
this storage comprises the disks in the storage system itself. On some models there are dedicated
disks for the operating system; on others the operating system and backup data storage are all on
the same disks.
•
The HP StoreOnce 4900 head server unit has two disks only, which are used for the operating
system and filesystem. If one disk fails, the server unit will continue to operate but the failed
disk should be replaced immediately. The HP StoreOnce 4900 Backup system always requires
one disk enclosure with base storage of 11 disks for user data + 4 hot spare disks. Up to five
additional expansion kits may be added to the disks in the first disk enclosure to increase the
backup data capacity, also RAID 6. These disks are configured in RAID 6 pools, such that
two disks per pool can be lost without loss of backup data.
One further disk enclosure can be added to the system, and is connected to the second RAID
controller card. Up to five additional expansion kits may also be added to the disks in the
second disk enclosure to increase the backup data capacity, and the storage expansion model
as the same as for the first disk enclosure.
There are two hot spare disks in each drawer of the disk enclosure, bays 34 and 35. If a data
disk fails, the hot spare disk will automatically be used until the failed disk is replaced. It will
only be returned to its status of hot spare disk when the data has fully rebuilt on the replacement
disk. The hot spare disks provide RAID 6 redundancy for the volumes within each drawer.
However, it is important to replace failed or predictive failing disks as soon as possible. If
more than two disks fail in the same pool, the system will fail and data will be lost. See the
HP StoreOnce 6500 Backup system Maintenance and Service guide for more detailed
information.
•
The HP StoreOnce 4700 head server unit has two disks only, which are used for the operating
system and filesystem. If one disk fails, the server unit will continue to operate but the failed
disk should be replaced immediately. The HP StoreOnce 4700 Backup system always requires
one enclosure of 12 disks for user data, these disks are in a RAID 6 set, such that two disks
per enclosure can be lost without loss of backup data. Up to seven additional enclosures may
be added to increase the backup data capacity, also RAID 6. The HP StoreOnce 4700 supports
daisy chaining.
RAID configuration 159