Memory Mirror Functions; Memory Sparing Function; Reserved Sb Function; Hardware Raid - Fujitsu PRIMEQUEST 2000 Series General Description Manual

CHAPTER 1 Product Overview
1.4 Hardware technologies

1.4.4 Memory Mirror Functions

The memory is duplicated and the data is written to both of duplicated memories. Even if an uncorrectable
error occurs in one memory, the data in the other memory can be used. This prevents the data errors which
cannot be corrected by Error Checking Correction (ECC), such as multi-bit error, which attains a continuous
and stable system operation.
In the PRIMEQUEST 2000 series, the Memory Mirror function is selected from the following Memory
Operation Mode.
- Full Mirror Mode: All memory in all SB of specific partition is mirrored.
- Partial Memory Mirror: The memory included in only the Home SB of the partition is duplicated.
Using the Memory Mirror, the partition can keep operating even if duplicated memory fails. The failed
memory will be removed from the partition (memory degradation) at next reboot. The operation when there is
memory degradation due to a memory fault can be selected from the following.
- Mirror Keep Mode: The memory duplication is maintained even after memory degradation.
- Capacity Keep Mode: The memory capacity is maintained by cancelling the memory duplication either
partially or in full.
For the details on the Memory Mirror function, see '3.2.5 Memory Mirror' in "PRIMEQUEST 2000 Series
Administration Manual" (C122-E175EN).

1.4.5 Memory Sparing Function

The PRIMEQUEST 2000 series is provided with a Memory Sparing function.
The Memory Sparing function prepares spare rank (a rank means unit of the block of memory module.) to
endure rank errors. If predictive failure of a rank is detected, copying the data of the rank into the spare rank
not to use failed rank will be able to keep the partition operating.
The Memory Spare function is enabled by the MMB Web-UI.
Note
In Intel® Xeon® processor E7 v2 product family, Memory Sparing between CPU sockets and between DDR
Channels is not supported. When using Memory Sparing, it is necessary to mount the DIMM in such a way
so as to have multiple Ranks in a DDR Channel. If Memory Spare Mode is selected at the order placement,
corresponding PRIMEQUEST systems are shipped in such a way so as to fulfil this condition.

1.4.6 Reserved SB Function

PRIMEQUEST 2400E and 2800E models support Reserved SB function.
The Reserved SB function is the function where a faulty SB is automatically removed from the partition, and
the Reserved SB which is previously configured is added to a partition when the partition is powered on.
SB reserved for switching at the time of failure, is called Reserved SB. Since the partition is automatically
reconfigured / restarted, there is improved operation continuity.
For details on the Reserved SB function, see '3.2.3 Reserved SB' in "PRIMEQUEST 2000 Series
Administration Manual" (C122-E175EN).

1.4.7 Hardware RAID

The PRIMEQUEST 2000 series supports hardware RAID. The hardware RAID has a dedicated RAID
controller chip and firmware. It can independently control an array by disconnecting the hard disk where
error had occurred, and connecting a spare disk or new normal hard disk.
The RAID levels supported by the hardware RAID are RAID 0, RAID 1, RAID 5, RAID 6, RAID 1E, RAID 10,
RAID 50, and RAID 60.
In SAS RAID controller card, a dedicated super-capacitor can be connected. The Write performance of RAID
5 and RAID 6 can be improved by enabling the Write Back Cache.
The SAS RAID controller card necessary for the hardware RAID should be mounted in the SB and DU.
Below table shows the number of HDD/SSD that is connected to a SAS RAID controller card in the DU and
shows
The number of HDD / SSD that can be mounted for each SAS RAID controller card in the DU is listed in the
table below.
14 C122-B025-02EN