![]() |
Create Array |
![]() |
![]() |
![]() |
RAID-0 | RAID-1 | RAID-5 | RAID-10 | FAST W |
There are two steps which must be completed when creating a new array.
This help is divided into sections :
Data Striping Data Mirroring Data Striping with Parity Mirrored Data Striping Resources which use the Fast Write Cache
( RAID-0, 1, 5 & 10 )
( Select the RAID type below )
RAID-0
3 to 16 member disks.
RAID-1
2 member disks.
RAID-5
3 to 16 member disks.
RAID-10
4 to 16 member disks, in steps of 2.
Fast Write
(RAID-10 Fast Write Array Shown)
Common Attributes: |
![]() |
Resource Name: On a PC Server you have to
enter a unique name for the new array. On AIX, this name is generated
automatically. Number of Components: The number of physical
disks components, or members, in the array. Block Size: The physical block size
of the records in the array. This must be 512.
Support of 524 is for a specialised application. Network ID: This identifies which SSA loop
is being used.
Array members must all be on the same SSA loop.
Note:
Additional 'Hot-spare' Attributes: (Common to RAID-1, 5 & 10) |
![]() |
All array types, except RAID-0, can make use of Hot-spare resources to further enhance the availability of the SSA subsystem.
Hot-spare Enabled:
This should be set to 'On' to enable the use of Hot-spares.
If this is set to 'Off', the array cannot use any available
Hot-spare disks if required. The array will move to a
degraded state.
Default: On Supports: On, Off
Note:
Hot-spare Exact Size:
Default: | Off |
Supports: | On, Off |
When Hot-spare exact is set to 'On', only hot spares of exactly the same size as the failing disk will be used. When Hot-spare exact is 'Off', the Hot-spare used may have a greater capacity than the failing disk it is replacing.
Additional 'Hot-spare Pool' Attributes: (IBM Advanced SerialRAID/X Adapter Only) |
![]() |
With the Adanced SerialRAID Adapter, all array types, except RAID-0, can make use of Hot-spare Pool resources. These Pools further enhance the availability of the SSA subsystem.
When assigning a Hot-spare Pool to protect an array, please ensure
the pool contains the correct capacity of resources as the array. i.e.
the pool contains resources with the same or greater capacity as the array
member resources.
Note:
Hot-spare Splits:
When Hot-spare Splits is set to 'On', and only one half of the RAID-10,
or RAID-1 array is available for use; Hot-spare
disks will still be used, if required, from the chosen or available pools.
When Hot-spare Splits is set to 'Off', hot-spare disks will not be used if
only one half of the RAID-10, or RAID-1 array is available. Hot-spare Preferred:
When Hot-spare Preferred is set to 'On', only a hot-spare from the
preferred Hot-spare pool will be used to replace a failing disk. When
Hot-spare preferred is 'Off', a suitable Hot-spare from a Hot-spare pool
other than the preferred pool may be used to replace a failing disk if
the preferred Hot-spare pool is empty. Pool 0 will be tried first, then
any other available pools.
If Hot-spare preferred is 'On', Hot-spare disks in the global
pool 0 will not be used.
Default: Off Supports: On, Off
Default: Off Supports: On, Off
Note:
When assigning a Hot-spare pool to protectan array, please ensure the pool contains the correct capacity of resources as the array, i.e. the pool contains resources with the same or greater capacity as the array member resources
![]() |
Additional 'RAID-0' Attributes: |
![]() |
Note: | RAID-0 arrays can consist of three to sixteen components. The larger the number of components, the more the data is spread across disks and performance is increased. The disadvantage of a large number of components is that as RAID-0 provides no redundancy and data is striped across all the member disks, the loss of a single disk results in the loss of more data. |
RAID-0 attributes depend on which adapter created the array.
Select your adapter from this list to view the relevant attributes.
Additional 'RAID-0' Attribute: when created with the RAID-0 Arrays created with this adapter have
the following attribute. This is in addition to the
Common attributes outlined above. The Block Size can only be 512
with this adapter.
Strip Size:
This defines the number of contiguous blocks held on
a disk before switching to the next disk. Larger values may result in worse
performance for long transfers as the data may be striped across fewer disks.
Lower values can result in worse performance for writes. Additional 'RAID-0' Attribute: when created with the RAID-0 Arrays created with either of these adapters have
the following attribute. This is in addition to the
Common attributes outlined above.
Strip Size:
This defines
the number of contiguous blocks held on a disk before switching to the next
disk. Larger values may result in worse performance for long transfers as
the data may be striped across fewer disks. Lower values can result in worse
performance for writes. Additional 'RAID-1' Attributes: RAID-1 arrays can only consist of two components.
IBM SSA RAID Adapter (LL03 and LL11)
Note:
Default: 32 (Blocks) PC Supports: Min 8, Max 8192 in steps of 1
IBM Advanced SerialRAID/X Adapter
Default: 32 (Blocks) PC Supports: Min 8, Max 512 in steps of 8
Note:
The attributes of your RAID-1 arrays will depend on
the adapter that created the array. Select your adapter from this
list to view the RAID-1 attributes your adapter will present.
Additional 'RAID-1' Attributes: when created with the RAID-1 Arrays created with either of these adapters will have
the following attributes. These are in addition to the
Common and Hot-spare
attributes outlined above.
Initial Rebuild:
When Initial Rebuild is set to 'On', the array will initially be
rebuilding and will copy the data from the first component to the second.
If this bit set to 'Off', the array starts life with its contents undefined,
and will immediately become non-degraded. This attribute can only be used at creation time, and cannot be
subsequently be changed. This attribute also insists that the first component
has less than or an equal number of data blocks as the second. With the Initial Rebuild bit set to 'On' and user data has yet to be written to the array,
the same data will be returned by whichever member disk is read. If the attribute
is 'Off', it is not guaranteed to always return the same data for the same
block before that block contains user data. It is recommended that the Initial Rebuild attribute is set to 'On', to
avoid possible problems if applications depend on
the same data returned before data is written. Note that this will incur
some performance overhead while the array is being
rebuilt. Data Scrub Enabled:
When Data Scrub Enable is set to 'On', the array will, when it is
non-degraded, verify in the background that all
the data for the array on the member disks can be read without error.
If an error is detected during this verification, the failing block on the
disk is repaired by rewriting the data from the mirrored array member
disk. Data Scrub Rate:
The Data Scrub rate sets the time in hours for the period of a single pass
of data scrubbing the array. The default time is 24 hours. A shorter time
incurs more interference with processing requests but detects latent failures
earlier. Rebuild Priority:
A higher value will result in faster array rebuilds, but may
reduce the performance of applications during the rebuild period.
A lower value will result in slower array rebuilds, but may increase
the performance of applications during the rebuild period. Split Confirm: When Split Confirm is set to 'On', an array with only one member
disk, and previously both member disks were not attached to this adapter,
is not brought online and an SSA event is generated. This provides
protection from a member disk being moved to another system and then
being used whilst the other disk of a mirrored pair is still being used
on the original system.
IBM SSA RAID Adapter or the
IBM SSA RAID Cluster Adapter
Default: Off Supports: On, Off
Note:
Default: Off Supports: On, Off
Default: 24 (hours) Supports: 6 to 48 (hours) in steps of 1
Default: 50% Supports: 1% to 100%
IBM SSA RAID Cluster Adapter Only
Default: Off Supports: On, Off
![]() |
Additional 'RAID-1' Attributes: when created with the |
RAID-1 Arrays created with this adapter will have the following attributes. These are in addition to the Common and Hot-spare attributes outlined above. For further information see the help which explains Multiple Domains and Component Ordering.
Split Array Resolution:
This should normally be set to 'Primary' When it is set to 'Secondary', the system only needs access to the secondary domain to continue operation if it has lost access to the other using system and the primary domain. This should only be set to 'Secondary' when you are sure that the other using system has lost access to and is not using the Primary Domain. If the fault has occured in the SSA loop, for example a cable fault, and the other using system is still using the Primary Domain, both systems will be able to access the two domains independantly which will result in unsynchronised data. Cluster Mode Only
Default: Primary Supports: Primary, Secondary
Initial Rebuild:
Default: | Off |
Supports: | On, Off |
When Initial Rebuild is set to 'On', the array will initially be rebuilding and will copy the data from the first component to the second. If this bit set to 'Off', the array starts life with its contents undefined, and will immediately become non-degraded.
This attribute can only be used at creation time, and cannot be subsequently be changed. This attribute also insists that the first component has less than or an equal number of data blocks as the second.
With the Initial Rebuild bit set to 'On' and user data has yet to be written to the array, the same data will be returned by whichever member disk is read. If the attribute is 'Off', it is not guaranteed to always return the same data for the same block before that block contains user data.
Note: | It is recommended that the Initial Rebuild attribute is set to 'On', to avoid possible problems if applications depend on the same data returned before data is written. Note that this will incur some performance overhead while the array is being rebuilt. |
Rebuild Priority:
Default: | 50% |
Supports: | 1% to 100% |
A higher value will result in faster array rebuilds, but may reduce the performance of applications during the rebuild period. A lower value will result in slower array rebuilds, but may increase the performance of applications during the rebuild period.
![]() |
Additional 'RAID-5' Attributes: |
![]() |
Note: | RAID-5 arrays can consist of three to sixteen components. The larger the number of components, the worse the performance may be for long transfers. However, the larger the number of components, the greater the reduction in the overhead of the parity function. Therefore the available capacity is maximised by using a larger number of components. |
RAID-5 attributes depend on the adapter that created the array. Select your adapter from this list to view the relevant attributes.
![]() |
Additional 'RAID-5' Attributes: when created with the |
RAID-5 Arrays created with this adapter will have the following attributes. These are in addition to the Common and the 'Hot-spare' attributes outlined above.
Strip Size:
This defines the number of contiguous blocks held on a disk before
switching to the next disk. Larger values may result in worse performance
for long transfers as the data may be striped across fewer disks. Lower
values can result in worse performance for writes but incur a longer
rebuild time when a failed component is replaced. Stretch Size:
This is the number of strips before the disk that holds the
parity data is changed. The default value is 4 and there is nothing to be
gained by using any other value. Rebuild Priority:
A higher value will result in faster array rebuilds, but may
reduce the performance of applications during the rebuild period.
A lower value will result in slower array rebuilds, but may increase
the performance of applications during the rebuild period.
Default: 128 Supports: 128 Only
Default: 4 Supports: 1 to 9999 in steps of 1.
Default: 50% Supports: 1% to 100%
![]() |
Additional 'RAID-5' Attributes: when created with the |
RAID-5 Arrays created with either of these adapters will have the following attributes. These are in addition to the Common and 'Hot-spare' attributes outlined above.
Strip Size:
This defines the number of contiguous blocks held on a disk
before switching to the next disk. Larger values may result in worse
performance for long transfers. Lower values may result in worse performance
for writes but incur a longer rebuild time when a failed component is
replaced. Stretch Size:
This is the number of strips before the disk that holds the
parity data is changed. The default value is 4 and there is nothing to be gained
in using any other value. Rebuild Priority:
A higher value will result in faster array rebuilds, but may
reduce the performance of applications during the rebuild period.
A lower value will result in slower array rebuilds, but may increase
the performance of applications during the rebuild period.
Default: 128 PC Supports: 32, 64, 128
Default: 4 Supports: 1 to 9999 in steps of 1
Default: 50% Supports: 1% to 100%
![]() |
Additional 'RAID-10' Attributes: when created with the |
![]() |
RAID-10 Arrays are only supported by the IBM Advanced SerialRAID/X Adapter. Such arrays have the following attributes in addition to the Common and the 'Hot-spare' attributes outlined above. For further information see the help which explains Multiple Domains and Component Ordering.
Note: | RAID-10 arrays can consist of four to sixteen components. The larger the number of components, the more the data is spread across disks and performance is increased. With a finite number of disks available for RAID-10 arrays, best performance is achieved with an equal number of RAID-10 arrays on each SSA loop. |
Strip Size:
This defines the number of contiguous blocks held on a disk before
switching to the next disk. Larger values may result in worse performance
for long transfers as the data may be striped across fewer disks. Lower
values can result in worse performance for writes but incur a longer
rebuild time when a failed component is replaced. Split Array Resolution:
This should normally be set to 'Primary' When it is set to 'Secondary', the system only needs access to the secondary domain to continue operation if it has lost access to the other using system and the primary domain. This should only be set to 'Secondary' when you are sure that the other using system has lost access to and is not using the Primary Domain. If the fault has occured in the SSA loop, for example a cable fault, and the other using system is still using the Primary Domain, both systems will be able to access the two domains independantly which will result in unsynchronised data. Cluster Mode Only
Default: 32 Supports: 32, 64, 128
Default: Primary Supports: Primary, Secondary
Initial Rebuild:
Default: | Off |
Supports: | On, Off |
When Initial Rebuild is set to 'On', the array will initially be rebuilding and will copy the data from the first component to the second. If this bit set to 'Off', the array starts life with its contents undefined, and will immediately become non-degraded.
This attribute can only be used at creation time, and cannot be subsequently be changed. This attribute also insists that the first component has less than or an equal number of data blocks as the second.
With the Initial Rebuild bit set to 'On' and user data has yet to be written to the array, the same data will be returned by whichever member disk is read. If the attribute is 'Off', it is not guaranteed to always return the same data for the same block before that block contains user data.
Note: | It is recommended that the Initial Rebuild attribute is set to 'On', to avoid possible problems if applications depend on the same data returned before data is written. Note that this will incur some performance overhead while the array is being rebuilt. |
Rebuild Priority:
Default: | 50% |
Supports: | 1% to 100% |
A higher value will result in faster array rebuilds, but may reduce the performance of applications during the rebuild period. A lower value will result in slower array rebuilds, but may increase the performance of applications during the rebuild period.
![]() |
Additional 'Fast Write' Attributes: when created with the |
![]() |
See the Fast Write Attributes in the array view help.
Actions:
This action submits the attributes and displays a list of suitable
candidates. This action create a new array, with the chosen attributes. You will not
be asked to select the components from the candidate
list, the first n appropriate 'Free'
disks will be chosen - where n is the number of
components in the array. All disks will be the same size - if possible. When Auto is selected on IBM Advanced SerialRAID/X Adapter, the array will be assigned to the global hot-spare pool on the given SSA Loop, that is either pool A0 or B0 - unless this pool does not exist, when the lowest numbered available pool is used. If no hot-spare pools exist, the global pool will be created and the array assigned to this pool. This action aborts the array creation, and returns to the relevant
Resource List. IBM Advanced SerialRAID/X Adapter Only
OK
Auto
Cancel
Confirm
This action displays the RAID-10 Confirmation page.
If you have chosen to create your RAID-10 array using multiple domains
this page allows you to check that you have assigned the resources to the
correct domain. You can flash the indicator lights on either half
of the array as part of this confirmation.
Related Information