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Service Hints & Tips |
Document ID: GSMH-3EMDX9 |
Servers - Hot-swap fixed disk drive replacement
Applicable to: World-Wide
Service Information
The IBM SCSI and RAID adapters have been designed to allow hard disk drives in hot-swap bays to be removed or installed while the system is running. In some situations, hard disks may be powered down by a RAID Adapter prior to their removal from a hot-swap bay (e.g. failed disk drive); however, this is not a fundamental requirement prior to removing a drive. Only persons trained and knowledgeable in RAID Array service procedures should attempt to service this type system, due to the exposure to possible customer data loss.
When removing drives which are still running, extra care needs to be taken.
The following facts should be understood:
1. The drive needs to be part of a FAULT TOLERANT RAID 5 or RAID 1 Array or the operating system may be unable to access data after the disk drive has been removed.
2. Only RAID 1 or RAID 5 Arrays allow dynamic rebuilding on a drive that has been replaced.
3. Only one disk drive can be rebuilt at a time.
4. The current level of RAID Administration Utility for the specific operating system should be run during disk drive removal. The RAID Adapter marks the drive DDD in this Utility to indicate a command was issued to the drive with no response.
5. Once a drive's status appears as DDD, a replacement drive can be inserted into the bay.
An operator can force a drive which has already been removed from a hot-swap drive bay to be marked DDD by invoking the Drive Information option in the RAID Administration utility. This option is available in all operating systems.
6. Fixed disk drives are fragile. Care should be taken to avoid rough handling of these devices. Care should also be used when plugging and unplugging hot swap drives to prevent damaging connectors, etc. Use ESD procedures.
When not installed in a system unit, drives must be protected by being packed in an antistatic bag and option/FRU pack or equivalent. When drives are being handled outside of their packaging the must not be subjected to a shock greater than the equivalent of being dropped 1 inch onto a hard surface. Any shock greater than this level may damage the disks within the fixed disk assembly and could also result in motor bearing damage which may result in noisy operation.
7. When power is removed from a hot swap drive by the RAID Controller or by user action, the drive will immediately park the heads, lock the actuator in the "landing zone", and begin spinning down. However, the disk spin-down may require up to 20 seconds after power removal. Moving the drive during spin-down should be AVOIDED.
In the event a drive is to be removed from or inserted into a hot-swap bay, the following procedures should be followed.
Steps for Removal of Hot-Swap Drives:
1. Unlatch the drive and gently unseat the drive from the backplane, but do not remove the drive completely from the hot-swap bay.
2. Wait 20 seconds to allow the disk drive to spin-down completely before removing it from the hot-swap bay.
3. Carefully remove the drive from the hot-swap bay.
Steps for Insertion of Hot-Swap Drives:
1. Ensure the current RAID Administration Utility is running for the specific operating system.
2. Verify the hot-swap bay where the drive is being inserted appears as DDD in the RAID Administration Utility.
3. Carefully insert the drive into this hot-swap bay.
4. Gently seat the drive completely in the backplane connector and latch the drive into the bay.
5. Follow the directions that came with the system documentation or RAID Adapter to activate the new disk drive and/or begin a data rebuild operation.
On IBM systems, where a Hot-Spare drive is available, the data rebuild operation will begin automatically without the requirement to replace the failed drive. In cases where a Hot-Spare drive is not available, the user or system administrator must use the RAID Administration Utility to initiate the drive rebuild operation.
As stated earlier, this procedure may differ from implementation by other vendors. Some other vendors' systems may rebuild data automatically when a new drive is inserted. Our procedure requires the user to request the data be rebuilt through the RAID Adapter Utilities in the case where a hot spare drive is not available. This provides the flexibility to reuse the remaining drives as part of another array without performing a rebuild operation, or to start and monitor the rebuild operation when it is convenient for the customer. If automatic unattended rebuild support is desired, then a Hot-Spare drive should be defined.
Note 1:
It is recommended that RAID system users periodically perform an "Array Synchronization" (perhaps twice a month) in order to help prevent future rebuild failures. This can be done either via the standalone RAID Adapter Support Diskette in an off-line mode, or while the server is running via the Netfinity RAID services menu.
Note 2:
In situations where RAID hot-swap "demostrations are being conducted, it is important that Drive Synchronization be done
prior to forcing a drive "dead" via a "hot-pull" of a working drive.
The drive that was pulled "hot" must then be either replaced into the array and completely rebuilt, or it must be configured
into another array and synchronized prior to being used to store data. This is because the act of "hot-pulling" a disk
could result in a partially written sector which would then need to be re-written to correct the ECC bytes or else that partially written sector could cause a rebuild failure later, if used in another array that was not completely synchronized.
SAS Keywords:
PSY2 RAID SERVER PSY2FDSK
SCSI SCSI-2 ARRAY D/T9595
D/T9595A D/T8641 D/T3516 320
D/T8640 8640 9595 9595A
8641 500 95 EXPANSION
ENCLOSURE 720 8642 D/T8642
INITIALIZE SYNCHRONIZE
Search Keywords |
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Hint Category |
Hard Drives, Retain | |
Date Created |
23-02-96 | |
Last Updated |
11-01-99 | |
Revision Date |
11-01-2000 | |
Brand |
IBM PC Server | |
Product Family |
PC Server 320, PC Server 500, PC Server 520, PC Server 720, Server 95 | |
Machine Type |
8640, 8641, 8642, 9595 | |
Model |
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TypeModel |
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Retain Tip (if applicable) |
H093102 | |
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