Originally posted by: Kimmel
With the announcement of 10 January (http://www.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/6/877/ENUSZG17-0006/index.html), IBM brings out a series of three DS8880 all-flash models,
- DS8884F — "Business Class"
- DS8886F — "Enterprise Class"
- DS8888F — "Analytics Class"
which each are based on the second generation of the "High-Performance Flash Enclosure" (HPFE Gen-2).
HPFE Gen-2
HPFE is a dedicated flash architecture with all-Custom Flash Hardware (CFH), which is specifically designed for the high IOps counts that take place when using flash. HPFE Gen-2 comes in paired enclosures of up to 48 flash cards, which as special hardware have the so-called "Microbays" in the rear.
Each Microbay, among other components, contains
- a Flash RAID adapter, which is dual-core PowerPC-based and hence can process RAID parity, and speed and amount of I/O in a way that goes far beyond of what a usual Device Adapter could handle, and
- a PCIe switch card. The switch card carries the signal forward from the Flash RAID adapters over via PCIe Gen-3 directly into both processor complexes of a DS8880F.
The Flash RAID adapters go with 8 SAS connections per Microbay pair to a pair of the specific flash enclosures, that hold SAS expanders and the flash cards.
All pathing is redundant. The HPFE Microbays are directly attached to the I/O enclosures by using the PCIe bus fabric, which increases bandwidth and transaction-processing capability compared to Fibre-Channel attached standard drive enclosures. The IBM DS8880 provides dual 8-lane PCIe connections to each HPFE, doubling the bandwidth that was available in the IBM DS8870. The HPFE Gen-2 makes full use of the PCIe Gen-3 connection protocols.
Flash cards for HPFE Gen-2 are available in capacities of 400 GB, 800 GB, 1.6 TB and 3.2 TB. The biggest model DS8888F can hold up to 384 flash cards today (=currently up to 1.23 PB raw), with further capacity increases expected.
At the same time, DS8880 remains to be offered as hybrid machine in a mix with HDDs (2-tier, or 3-tier), or as full-SSD machine with up to 1536 SSDs, which makes DS8880 to one of the most versatile systems in terms of scaling.
SPC-1 v3 Benchmark
The DS8888 (model 982), which is the predecessor model of the new DS8888F (model 988) and which was based on HPFE Gen-1, has a submitted cross-vendor SPC-1 v3 benchmark result of 1,500,187 SPC-1 IOPS, combined with a SPC-1 Overall Response Time of 0.336 ms:
http://www.storageperformance.org/results/results_spc1_v3/results_spc1_v3_ibm/results_spc1_v3_ibm_a31002/SPC-1_A31002_ES_IBM-DS8888.pdf
These are record results, especially for a FICON-capable storage system delivering mainframe reliability.
With DS8888F, internal measurements have shown up to 2.5 million IOps in typical OLTP environments.
RAID-6
Another bigger change with the new DS8880 models (984, 985, 986, 988) is the recommendation for a RAID-6 default, alternatively to RAID-10, but instead of RAID-5. This includes the HPFE flash cards. RAID-6 comes with 2 parity drives in a RAID array. Our RAID-5 already has additional means of protection ("Smart Rebuild") compared to RAID-5 implementations of other vendors. But with drive capacities and hence also rebuild times ever increasing, over the years and in a relative comparison the drives have become a component that should be treated with highest redundancy, in order to achieve a maximum reliability. And this is true for all storage vendors. Hence when configuring the DS8880 e.g. in the GUI in an automated fashion, RAID-6 is suggested.
DS8880F models are generally available starting 20 January.
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DS8888F