Disclaimer: My information is older than my post, I did not find this forum for a while and decided to toss a few questions up. I’ll try to get an update from my colleague if possible.

on April 9th, 2008 at 5:28 pm

I have a question as to why the IOs are so low on the Arato box. Maybe the disks are slow or low quality??? The types of disks generally used in most sans are usually in the range of 300 IOPs per spindle on the high end (Fibre Channel),

Kelly,

I wonder what disks you had in mind when you said “usually in the range of 300 IOPs per spindle”.

I am not aware of any disk with the average seek time of 1.3ms. Therefore, I doubt that 300 IOPs are achievable with a random workload.

Also, what about heat? That’s the reason why no one has done this before. Can you imagine the heat put out in 3U with 100 drives? The fans have got to be turbine engines to keep the drives cool. Vibration and heat are drive killers.

Given the background of some of your technical people, I am sure that Atrato can tackle all of the required design tasks. However, firmware takes time to write and to become field-proven … and some issues are difficult to solve.
Additional answers would be helpful.

1. Given the number of disks and the four FC channels, the IOPS figures are believable.

However, it would be interesting to know what size of data payload is used for this test, separate numbers for reads and writes… if this is across one or two controllers … and the number of disks and LUNs per FC initiator.

2. It seems that the 3U system contains only one controller. Additional 2U enclosure is required for the second controller and presumably you do support multi-ported LUNs.

How is this connected for redundancy, power outages and how do you manage multi-ported LUN coherency…i.e. should the initiators span different asynchronous data sources (servers) ?

3. The 1.2 G Byte streaming figure…presumably this is under Raid 6 in a rebuild mode.

If not, then which Raid level was used and in what condition… i.e. degraded ?
Is this through a single controller and across the four FC channels ?

4. Your stated performance figures presumably hold or improve across coherent, dual-controller HA configuration ?

Thanks,
Richard

Today I wanted to address some of the questions on Robin’s blog with respect to the Atrato Velocity 1000 product line. The Atrato V1000 is a self- maintained array of identical disks (SAID) purpose-built for access and performance density. On average the V1000 will exceed 11,000 IOPS. I say on average because as most of you know performance numbers vary based on initiators, file systems, whether the file system utilizes cache, RAM configuration, and buffer schemes. In a specific configuration based on Windows Server 2003 Enterprise Edition with four 4G fiber channel links the V1000 will sustain well in excess of 11,000 IOPS in 3U. (The system also utilizes a 2U controller which can be interconnected for redundancy.) If the application is video streaming then the V1000 will support over 3000 standard definition streams or 1.2GB/s streaming capability. Having mentioned fiber channel, the V1000 system is a multiprotocol architecture today supporting 4Gig FC SAN and NFS NAS. Over the next few months Atrato will be announcing additional connectivity support. Pricing on the Atrato V1000 system varies based on customer configurations. Options for higher capacity or screaming performance will affect the configured price. The SAID utilizes 2.5 inch SATA drives which come in various RPM and storage capacity. The enclosure itself is configurable from 96 drives to 160 drives and higher densities to come. As you would expect the Atrato Virtualization Software allows for access of hundreds of drives across multiple arrays.

I appreciate the forum here and look forward to future dialog.

From what I’ve read, the spare drive allowance seems to be variable. They quote somewhere between 10-15% will be required over 5 years (although they use 3 pretty much everywhere in their report) which meets the stats I’ve seen quoted from that Google report and the other one (which I can’t recall right now) which basically say that failures start at 1% and increase by 1% every year on drives (1 + 2 + 3 + 4 + 5 = 15%).

Their RAID and predictive health software is what really impresses me about Atrato. They can do RAID10 (and a 3-way version), RAID50 and RAID60. With RAID10, they can preemtively rebuild a drive if they think one of them is about to fail and then pull & test it. They constantly (at a *background* rate) test all sectors on all their hot spares and they can reduce performance (and therefore power usage and heat generation) in environmental situations that would affect the lifetime of the device.

I hope there is something new in some of this.