Green Storage? Meh!

Something triggered my thoughts a few days ago. A few of us got together talking about climate change and a friend asked how green was the datacenter in IT. With cloud computing booming, I would say that green computing isn’t really the hottest thing at present. That in turn, leads us to one of the most voracious energy beasts in the datacenter, storage. Where is green storage in the equation?

What is green?

Over the past decade, several storage related technologies were touted as more energy efficient. These include

  • Tape – when tapes are offline, they do not consume power and do not require cooling
  • Virtualization – Virtualization reduces the number of servers and desktops, and of course storage too
  • MAID (Massive Array of Independent Disks) – the arrays spin down the HDDs if idle for a period of time
  • SSD (Solid State Drives) – Compared to HDDs, SSDs consume much less power, and overall reduce the cooling needs
  • Data Footprint Reduction – Deduplication, compression and other technologies to reduce copies of data
  • SMR (Shingled Magnetic Recording) Drives – Higher areal density means less drives but limited by physics.

The largest gorilla in storage technology

HDDs still dominate the market and they are the biggest producers of heat and vibration in a storage array, along with the redundant power supplies and fans. Until and unless SSDs dominate, we have to live with the fact that storage disk drives are not green. The statistics from Statistica below forecasts that in 2021, the shipment of SSDs will surpass HDDs.

Today the areal density of HDDs have increased. With SMR (shingled magnetic recording), the areal density jumped about 25% more than the 1Tb/inch (Terabit per inch) in the CMR (conventional magnetic recording) drives. The largest SMR in the market today is 16TB from Seagate with 18TB SMR in the horizon. That capacity is going to grow significantly when EAMR (energy assisted magnetic recording) – which counts heat assisted and microwave assisted – drives enter the market next year. The areal density will grow to 1.6Tb/inch with a roadmap to 4.0Tb/inch. Continue reading

Supercharging Ethernet … with a PAUSE

It’s been a while since I wrote. I had just finished a 2-week stint in Melbourne, conducting 2 Data ONTAP classes and had a blast.

But after almost 3 1/2 months of doing little except teaching NetApp classes, the stint is ending. I wanted it that way, to take a break and also to take on a new challenge. I will be taking on a job with Hitachi Data Systems, going back to the industry that I have termed the “Wild, wild west”. After a 4 1/2-year hiatus, I think that industry still behaves the way it is .. brash, exclusive, rich! The oligarchy of the oilmen are still laughing their way to the banks. And it will be my job to sell storage (and cloud) solutions to them.

In my Netapp (and EMC) engagements in the past 6 months, I have seen the greater adoption of iSCSI over Fibre Channel, and many has predicted that 10Gigabit Ethernet will be the infliction point where iSCSI can finally stand shoulder-to-shoulder with Fibre Channel. After all, 10 Gigabit/sec is definitely faster than 8 Gigabit/sec Fibre Channel, right? WRONG! (I am perfectly aware there is a 16 Gigabit/sec Fibre Channel, but can’t you see I am trying to start an argument here?)

Delivering SCSI data load over iSCSI on 10 Gigabit/sec Ethernet does not necessarily mean that it would be faster than delivering the same payload over 8 Gigabit/sec Fibre Channel. This statement can be viewed in many different ways and hence the favourite IT reply would be … “It depends“.

I would leave this performance argument for another day but today we are going to talk about some of the key additions to supercharge 10 Gigabit Ethernet for data delivery in storage networking capacity. In addition, 10 Gigabit Ethernet is the primary transport for Fibre Channel over Ethernet (FCoE) and it is absolutely critical that 10 Gigabit Ethernet must be close to as reliable as Fibre Channel for data delivery in a storage network.

Ethernet is a non-deterministic protocol, and therefore, its delivery result is dependent on many factors. Likewise 10 Gigabit Ethernet has inherited part of that feature. The delivery of data over Ethernet can be lossy, i.e. packets can get lost and the upper layer application protocols will have to respond to detecte the dropped packets and to ensure lost packets are redelivered to complete the consignment. But delivering data in a storage network cannot be lossy and in most cases of SANs, the requirement is to have the data arrive in the sequence they were delivered. The SAN fabric (especially with the common services of Layer 3 of the FC protocol stack) and the deterministic nature of Fibre Channel protocol were the reasons many has relied on Fibre Channel SAN technology for more than a decade. How can 10 Gigabit Ethernet respond?

Continue reading