About 12 months ago a disruptive influence joined our team, a Microsoft Dynamics AX consultant, who certainly makes us question the way we do things. In the new landscape he has come to help roll-out, we are using SQL Server 2014 Enterprise Edition in an Always-On configuration. We anticipate the main database to to grow to about 2 TB over the next 3 years.
For about 4 years now we have been using a HP4500 and HP4730 RAID 10 over RAID-5 storage arrays. In the new landscape, we are using SQL Server 2014 Enterprise Edition in ab Always-On configuration They have served us well but this guy immediately came at us with questions and statements:
- Why are you using a SAN. It is too slow for Microsoft Dynamics? You should be using SSD.
- SSD will make your recovery window so much smaller that you won't be concerned about mirrored SANs across separate data halls as you'll be able to restore and recover well within the SLA for much less cost.
So we did a trial:
- Firstly with SATA SSDs which did not impress at all. Throughput was fine, but latency was dreadful, overall performance no better than what we are seeing on the SAN.
- Secondly we tried PCIe SSDs, which plug in to the server like a memory card. The increase in i/o was nothing short of astonishing being at least an order of magnitude better and depending on the workload several orders of magnitude better.
So we now have the interest of the CIO and basically I need to do some research to find out:
- What is the market penetration of SSDs in SQL Server ?
- How many people are using on business critical ERP systems?
- Is any using them as primary storage?
- Are they just being used for tempdb and/or the transaction log?
- How resilient are they? What are DR/HA options.
- We have the benefit of Always-On if one node should fail so should be able to maintain continuity.
- This still does not feel as resilient as 100s of spinning disks in a storage array
- RAID 5 storage units striped over the storage units.
- in turn mirrored to a second data centre.
- Even so, possibly due to complexity this set up has not been trouble free.
So my basic question is PCIe: Suitable for primary storage or not? Are you doing it? Would you do it? How are you mitigating the risk of a server with on-board storage failing?