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PLA-Support>Sun Systems>DISK>Axiom>SN-DK: Ax600
 

In this Document

Purpose

Scope

Details

Using larger capacity drives

Ordering and Dispatching Replacement Hard Disk Drives

Applies to:

Purpose

The purpose of this document is to describe the practice of replacing brick hard disk drives with drives that have a capacity greater than or equal to the faulted drive. The additional purpose of this document is to describe the RAID Configuration layout of a Pillar Axiom Brick

Scope

  Internal Information Only

A couple of points to consider when replacing older SATA drives:

1. The brick must be running in an Axiom on 03.03.13 and above to accept a 2TB drive.
2. The 2TB Mars K drive, which is our current production drive, has SATA interface speed (1.5Gb/sec). Gen 1 RAID controllers do not support speed negotiation so sometimes they work and sometimes they don’t. The Jupiter U 1TB and 500Gb drive has its speed set to 1.5Gb/s so they are OK. The Mars KP 2TB drive that we have qualified as the universal spare has its frequency fixed at 1.5Gb/s so these are compaticle with all bricks and are valid replacments.
3. NOTE: The Mars-KP 2TB drive has custom Oracle firmware which includes a unique model number and the SATA interface speed was limited to 1.5Gb/s so that this drive could be used as a universal spare for all bricks currently in the field.  The Jupiter-U drive is 3Gb/s capable but we limit this to 1.5Gb/s through mode page settings performed in manufacturing.
4. For more information on Jupiter Drive Replacements, and what part numbers to use, please reference Pillar Axiom: Process to identify Hitachi Jupiter-U drive failures due to vibrations and remediation plan Doc ID 1596947.1

Details

Using larger capacity drives

Pillar Axiom bricks are designed to take replacement drives of equal or higher capacity.

As disk drive technology follow advancements in areal density, drive capacities continue to increase every year.  The Axiom bricks are configured with stripes of RAID arrays.  The effective capacity of any drive in the array is set by the size of the RAID array, not the size of the drive.  This size is set during the Brick initialization as a manufacturing process, and does not change.  This capacity is not affected by replacing a drive with one of a large capacity because the arrays are formed by stripes across multiple drives.

Oracle tests drive replacement for all supported drives whether they be of same or higher capacity and also drives from different manufacturers in order to maintain continuity of supply for spares.  If a larger drive is placed in an array, not all the capacity is used.  The performance of the array is not affected by using larger drives.

The Pillar Axiom 600 Service Guide states:Important! The capacity of the drive replacement must be equal to or greater than that of the other drives in the Brick enclosure. So the only absolute requirement for matching drive specs in a Pillar Axiom Brick during replacement, is that the drives must be of the same architecture, i.e, all FC or SATA and that the capacity of the replacement drive must be greater than or equal to the original.

SATA bricks RAID 5 arrays are laid out as above

Fibre Channel brick layout above is different

SATA RAID 10 layout

The layout of SATA RAID 10 (selected with Write bias) and wide stripe (selected as part of the Oracle ASM profile) are shown above.  As the array type is configured as a stripe across all drives in the array, it is possible to mix RAID types on the same disk array.  Disk zeroing is performed by the Axiom on unallocated stripes so that RAID integrity can be maintained when new data is placed on that stripe.

Ordering and Dispatching Replacement Hard Disk Drives

When arranging a dispatch for a hard disk drive that has failed in a Pillar Axiom Brick, Oracle Support will order a replacement using the original part number of the drive that failed. The part number to order is identified by Oracle Support using the Axiom callhome service logs received from the Axiom that experienced the hard disk drive failure.  

Oracle may substitute the ordered part number with an alternative part number of a hard disk drive with different capacity and/or model, that is validated and tested as an approved alternative. Oracle tests drive replacements for all supported drives whether they be of same or higher capacity and also tests hard disk drives from different manufacturers in order to maintain continuity of supply for spares. Therefore it is fully supported to use a replacement hard disk drive of equal or greater capacity within an Axiom Brick.

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