This will be the parent page for storage material. It is being reorganized into topic specific sections.
Storage 2017 (2017-03),
Transaction IO Performance on Violin (2015-02),
Storage by Topic
|EMC||CLARiiON AX4||CLARiiON CX4
Vendors: Dell, HP, IBM, EMC, Hitachi, others
This will be the same material as in the Direct-Attach and SAN sections above, except it will be organized by vendors. I will do this after the category sections are complete.
RAID: there is plenty of material from other sources on RAID levels, so I will not cover this for now.
Storage Articles - Older
Below are the older storage articles. Excerpt from the original and new updates will be incorporated into the new structure-sections above.
Storage Performance for Data Warehouse (2010-10)
Storage Performance (2009)
Sometime in the next year, we should start seeing products with the NVM Express interface. A significant part of NVMe is the overhaul of the IO software stack. A IO API call to a SATA storage via ACHI (the SATA ports on a PC motherboard) squanders CPU-cycles in non-cacheable register reads, and other inefficiencies. None of this was an issue with SATA hard disk performance. Even a single recent generation SATA SSDs capable of 550MB/s and 90K IOPS did not overload the limits of AHCI.
For a large array of HDDs, the more efficient software stack of SAS and FC HBA's is very important. It is not just a matter of being able drive very high IOPS, but also with minimal impact on the host, so that the host CPUs can perform their primary mission, such as running the database engine, without being heavily disrupted by interrupts. This was sufficient to handle the IOPS possible from very large HDD arrays. One thousand disks at 200K IOPS are not a problem?
But for SSD arrays, 1M+ IOPS is not difficult, so the time has come to overhaul the software stack. There is an emphasis on not just efficiency but also scaling on multi-core processors and NUMA system architecture.
Does Intel Xeon E5 with X540 10GbE Data Direct IO (DDIO) direct to cache, no memory ?