Specifications

Escala Tower PL & S, E, T System Hardware
Chapter 3: External Storage and SAN Subsystems 18/116
9es3s1c3.doc
Rev 5.9
02/12/2003
2.1.4.4.4. Cooling Fans
iDAE enclosures are equipped with a drive fan pack that cools the disks and the SPs. The fan pack
contains 3 fans. If a fan fails, the speed of the remaining fans increases to compensate. If needed, a fan
pack can be removed for exchange operation while the storage system continues to operate (the
exchange operation, however, must not exceed two minutes, otherwise disks and SPs shut down).
2.1.4.4.5. Disk drives
The iDAE enclosures use the same disk than the other enclosures of the 5000 Series. The minimum
number of disks per iDAE enclosure depends on the number of SP. The maximum is always 10 disks,
but one or two DAE can be chained to increase the capacity of the array.
Minimum
(iDAE enclosure)
Maximum
(iDAE enclosure)
1 SP 3 10
2 SP 5 10
Disks are formatted with 520 bytes per sectors.
2.1.4.4.6. Memory
Each SP can have 64, 128 or 256 MB of memory.
The Flare (micro code running on the SP) requires 15 to 18 MB. The remaining 110 MB of memory
can be used as a read cache, or write cache, or a mixture of both, to improve the subsystem
performance.
To ensure data consistency in case of failure,
the write cache is always mirrored
, and the following
hardware configuration must be used:
•
Two SPs per iDAE
•
Two power supplies and two LCCs in the iDAE and in each DAE
•
Disk slots 0 through 4 of the iDAE enclosure must be populated.
•
One SPS with a fully charged battery (two SPSs provide higher availability)
•
Identical cache memory in both SPs (64, 128 or 256 MB per SP).
It is not possible to use write caching without mirroring across SPs and without the hardware
configuration described above. For example, it is not possible to configure a write cache on an iDAE
with a single SP.