Hitachi adds power-down to mid-range storage gear
Dr. Chandra? Will I dream?
Hitachi Data Systems is adding the ability to power down disk drives on demand to its mid-range product lineup. They're also rolling out support for bigger disks and some new security services.
The enhancements cover Hitachi's Adaptable Modular Storage (AMS) and Workgroup Modular Storage (WMS) gear.
The Power Savings Storage Service (PSSS, no — really) can be activated by the user or application when needed. PSSS will be available for SATA or Fibre Channel disk drives on all AMS and WMS systems.
For disk dabblers, such a service lets the HDD power down when its not being accessed and power back up when an application needs it. Powered down drives obviously don't need to be cooled and require less power, reducing the number of kilowatt hours a storage array consumes. Hitachi reckons it can delivery a 20 per cent cost-of-operation advantage versus your HDD plain and tall with the technology.
AMS and WMS systems now also support 750GB SATA II drives, which offer more capacity and reliability than your daddy's SATA drives of yesterday.
HDS is adding some security goodness too. AMS and WMS systems now feature audit logging and role-based access security services.
Both systems have added an Audit Log File, which stores a history of all user access operations performed on the system. The history includes information on the user(s), the precise time of operation, the name of the operation, any parameters set and the end result (that's either a normal completion or error message). Customers can export the log files from multiple systems to a centralized server to simplify the audit and control management tasks. The log is compliant with the BSD Syslog Protocol (RFC3164), which should let customers integrate with existing log shipping infrastructures.
Also added is a shiny new Role-Based Access Service. This provides user authentication and access control for more secure management of AMS and WMS configurations. Management can be controlled by individual user profiles with three levels of access: account administrator, storage administrator and auditor. Storage management functions can be restricted based on their specific profile. Each user has a unique login and password to limit them to their roles. ®
That's fine, until you have over a certain ammount of storage. I only really know EMC's DMX arrays, but you are looking at 3phase power, tens of amps at a time, you _really_ notice turning off a %age of a couple of hundred disks.
Where I work we have something like 18DMXs, that's a whole lodda power, and cooling. We mainly don't bother with disk based backups, because a tape library doesn't use a fraction of the power/heat footprint. We do however, keep two snapshots of each server, one on two different arrays. Now the trouble with DMX here is that each disk is chopped up into virtual devices, these are then presented to the different machines, this means that you have to make sure that all of the devices on each disk are presented to machines which won't be useing them at the same time. All you have to do is accidentally stick a database onto a disk containing snapshots and it'll never power down.
@Richard - Spin up/spin down
For myself personally, the energy costs in this really make no significant difference. Keeping a HDD alive and running and not having to swap it out is worth more than energy cost savings.
Spin up/spin down
The question of whether this is worth it depends on the cycle time, and is relatively simple to calculate.
Answer three questions:
1) How much energy is required to spin up the drive(s)?
2) How muich energy is used per second when is use?
3) How long is it going to stay off?
1 and 2 are dead easy, 3 is the tough one - by the time you know that you would have saved energy, it's too late to do so. So you have to predict it.
A few years ago I spent some time doing essentially the same calculations for a compressed air system - calculating the cost of pumping up the system from empty versus the cost of leaving it running over the weekend.
Surprisingly, it turned out to not really be worth it.
Same question, different context.