Infinidat has no plans to move from disk to quad-level flash for its capacity storage, arguing that all-flash arrays at scale are prohibitively expensive.
The high-end storage vendor make InfiniBox arrays with 10PB effective capacity and fast data access based on DRAM caching with an intermediate NAND tier. The company is prepping Availability Zone (AZ) clustering technology for release next year. This will cluster up to 100 Infinidat arrays, with effective capacity up to 1,000PB per AZ.
Infinidat argues all-flash arrays are a technological dead-end at multi-petabyte scale. Disk is cheaper per TB than flash, has a longer working life, and memory cacheing makes it faster than all-flash arrays.
Simply put, 1PB of disk is more affordable than 1PB of flash and needs less electricity. Scale that up to 1,000PB and the disk-vs-SSD cost and electricity usage differences are huge.
Three Infinidat execs briefed Blocks & Files to hammer home this message.
Their stance puts Infinidat at odds with rival array vendors Pure Storage, NetApp and VAST Data, a well-funded newcomer.
Recently-announced QLC flash SSDs are closer in price to disk drives and have a shorter write cycle total than mainstream TLC (3bits/cell) SSDs. Over-provisioning and controller software updates to zone areas of flash in the SSDs are intended to ameliorate this.
VAST Data relies on a single QLC flash tier for its capacity storage while NetApp intends to add QLC flash to its all-flash arrays next year. Pure Storage announced the QLC-using FlashArray//C in August this year. All three suppliers believe that a QLC capacity tier provides faster data access than nearline 7,200rm disk drives.
QLC ‘has horrid reliability’
Infinidat owes its existence to disk drives and invalidates the flash-will-kill-disk-drives thesis, CTO Brian Carmody said this week in a telephone briefing.
As enterprise data storage needs move into the exabyte era, NAND storage costs are simply too high. “Disk drives are going to save the enterprise storage industry,” he proclaimed.
His colleague Ken Steinhardt, field CTO, told us the company “could use QLC but the cost and reliability deltas are significant. QLC wouldn’t increase performance but would increase cost”.
Carmody added: “QLC is ten times more expensive than nearline SAS disk and has horrid reliability. Hyperscalers have zero interest in it.”
According to Stanley Zaffos, product marketing SVP, “small shops up to 100TB or so will be okay with all-flash arrays. Disk drives are more attractive at scale: 1,000TB and beyond.”
He noted: “Nearline drives are very competitive against SSDs on a TB/watt basis. At 0.8watts/TB the advantage gets even stronger as you scale out capacity to 10PB.”
And the future of disk drives? Carmody thinks multi-actuator disk drives, with a pair of read-write heads per platter, and championed by Seagate, are important: “We are working with major hyperscalers and drive manufacturers on hard disk drive roadmaps. Multi-actuation is huge. Seagate has a seat on our board and is an investor.”