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10.731 bytes |
Service Hints & Tips |
Document ID: SRUL-3DZKCK |
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Servers - ServeRAID adapter hints and tips
Applicable to: World-Wide
Description :
The PC ServeRAID SCSI Adapter option is a high-performance, three-channel, PCI RAID Adapter that supports up to 15 hard drives per channel with RAID levels 0, 1, and 5. It features an onboard RISC microprocessor to handle the complex RAID algorithms with blazing speed. It also contains a high-speed 4MB cache and a local PCI bus to further enhance performance.
IBM incorporates Logical Drive Migration with the PC ServeRAID SCSI Adapter that allows changes to be made to the RAID configuration while the Server is up and running. This adapter includes utilities for setup, display and administering of disk arrays for NetWare 3.x and 4.x, OS/2, Windows(1) NT and SCO.
À High-speed hard drive options provide extremely fast Lan Server Performance
À Drives are available in fast/wide versions, 1.12GB, 2.25GB or 4.51GB With average seek times of 8.0 ms, these high-speed drives spin at 7200 rpms to provide state-of-the-art server performance.
À IBM's high-speed drives when used with TME 10 NetFinity provide Predictive Failure Analysis (PFA), can alert the system administrator of an impending drive failure 24 to 48 hours before it happens.
For hard drives with this PFA feature covered by IBM warranty, IBM will replace the drive if the TME 10 NetFinity PFA service detects a failure.
Question:
With ServeRAID Adapter is it possible to :
migrate Raid 5 to Raid 0
migrate Raid 0 to Raid 5
increase all logical drive size (Raid 0, 1 or 5)
Will it be possible to :
migrate Raid 0 to Raid 1
migrate Raid 1 to Raid 5
and vice versa
Answer:
The ship level ServeRAID Adapter allows the user to do the following migrations:
Raid 0 to Raid 5
Raid 5 to Raid 0 (last drive defined in the array is removed)
during each of these operations, the logical drive is not accessible by the user.
The next release of ServeRAID software (available 1Q 97) will allow the user to do the following migrations:
Raid 0 to Raid 5
Raid 5 to Raid 0 (last drive defined in the array is removed)
Raid 1 to Raid 5 (only 2 drive Raid 1 to 3 drive Raid 5 is supported)
Increase the logical drive size of a Raid 0, Raid 1, or a Raid 5 by adding 1 to 3 physical drives to the array.
Increase the array size by adding 1 to 3 physical drives to the array.
During each of these operations, the logical drive is on line and accessible by the user.
Two other nice features of this software release allow a single drive failure in Raid 1 and Raid 5 configurations during migration and power failure during migration with the ability to restart the migration automatically when the system is powered on.
Question:
Is it possible to change an old Raid adapter in a 320 by the PC ServeRaid without re-installing the NOS ???
Answer :
If the customer has a mylex Raid adapter, he can import the drive configuration into ServeRAID. If the customer has any other storage Adapter he will have to backup all data, create the new arrays/logical drives on ServeRAID and restore his data.
Importing the configuration is as if you were replacing the adapter:
If a customer installs a new ServeRAID adapter to replace an old one (i.e. FRU) then when the system boots up, ServeRAID will ask the customer if he wants to import the configuration from his drives. After doing this, the ServeRAID adapter will have the correct configuration information.
Question:
My customer has an original ServeRAID Adapter, it does not support Logical Drive Migration ( LDM ), how do I obtain the LDM support ? Do I need to replace the adapter for a later level one ?
Answer:
If the customer has an existing ServerRAID adapter, all that needs to be done is to update the firmware, flash, and drivers that are used by the ServeRAID adapter.
Logical Drive Migration is a software change only.
Question:
What happens if an existing ServRAID adapter fails ?
What do we have to do to recover ?
Answer:
If a customer installs a new ServeRAID adapter to replace an old one (i.e. FRU) then when the system boots up, ServeRAID will ask the customer if he wants to import the configuration from his drives. After doing this, the ServeRAID adapter will have the correct configuration information.
Question:
Can I use the ServeRaid in the Server 704 today (if not, then when) ? do I need a HW, BIOS and/or firmware updates ?
What cables do I need ?
Answer:
ServeRAID will not work in the Server 704 until 1Q 97. a new level of Server 704 system BIOS is required.
This level of Server 704 system BIOS will make it possible for ServeRAID to be used in the Server 704 for external storage, i.e. with the 3518 expansion enclosure.
Support of internal disks on the Hot-Swap backplane using ServeRAID will be earlier than was first forecast, firm dates are not available for this (it is hoped however that this support will be at the same time as external support, i.e. first quarter 97, this is dependent on how testing goes). This will in addition to the new Server 704 system BIOS require a new firmware update on the ServeRAID adapter.
It is also hoped to support the Logical Drive Migration feature (LDM) with this firmware update.
This support of the internal Hot-Swap disks using ServeRAID is possible using the current Intel backplane and The same cabling can be used as is currently used with the Mylex RAID controller can be used.
Question :
Can you use the Server 704s Adaptec 7880 controllers for external devices ?
Answer :
I have been told that this is possible using the ServeRAID bulkhead cable, I would recommend using the cabling guidelines as outlined for the ServeRAID adapter, please see the Server 520/ServeRAID announcement.
Question
What is the ServeRaid Adapter Memory Type .... EDO ??
Answer:
1MB for the Code DRAM: Following parts are qualified by IBM
Samsung Electronics 256Kx16 (KM416C256/ALL-6)
Samsung Electronics 256Kx18 (KM418C256/ALL-6)
Samsung Electronics 1M4 QUADCAS (KM44C1003B-6)
Micron 256Kx16
4MB Data Cache DRAM : 2 1MX18 Fast Page DRAM, TSOP module (IBM 43G6205)
** Uses 4MB Fast Page, non-EDO Burlington chip. **
Note that no memory upgrade is available.
Question :
How is the cache organised in the ServeRAID adapter ?
Answer:
The 4MB cache on the ServeRAID adapter is direct mapped using a Least Recently Used (LRU) replacement algorithm to data blocks on the attached disk drives. The cache page size (allocation unit size) defaults to 8KB and changes according to the RAID Stripe Unit Size setting (8KB, 16KB, 32KB, or 64KB).
Other options for the cache include Write Back or Write Through modes and Read Ahead Enable/Disable. Write Through mode forces data being written to an array to be written to the disk drives before indicating to the operating system that the command has been completed.
Write Back mode allows the adapter to return a command complete indication to the operating system as soon as the data being written has been placed into the adapter's cache memory. This cache is standard DRAM and therefore if power is lost before the data is actually written to the disk drives, that data will be lost. In Write Back mode the data is written to the disks based on the LRU algorithm after 1 second of no activity or if percentage of write back data in the cache reaches 80%.
Read Ahead enable tells the adapter that accesses to the disk arrays will in many cases be sequentially reading data from the disk rather than randomly accessing data from the array. When Read Ahead is enabled, any time the adapter reads data from a disk, it will read enough data to fill to the end of the current cache page.
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Hint Category |
RAID | |
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Date Created |
05-02-97 | |
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Last Updated |
11-02-99 | |
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Revision Date |
11-02-2000 | |
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Brand |
IBM PC Server | |
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Product Family |
ServeRAID, Servers | |
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Machine Type |
Various | |
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