Micron’s new P300 SSD and SSD longevity

Micron P300 (c) 2010 Micron Technology
Micron P300 (c) 2010 Micron Technology

Micron just announced a new SSD drive based on their 34nm SLC NAND technology with some pretty impressive performance numbers.  They used an independent organization, Calypso SSD testing, to supply the performance numbers:

  • Random Read 44,000 IO/sec
  • Random Writes 16,000 IO/sec
  • Sequential Read 360MB/sec
  • Sequential Write 255MB/sec

Even more impressive considering this performance was generated using SATA 6Gb/s and measuring after reaching “SNIA test specification – steady state” (see my post on SNIA’s new SSD performance test specification).

The new SATA 6Gb/s interface is a bit of a gamble but one can always use an interposer to support FC or SAS interfaces.  In addition,today many storage subsystems already support SATA drives so its interface may not even be an issue.  The P300 can easily support 3Gb/s SATA if that’s whats available and sequential performance suffers but random IOPs won’t be too impacted by interface speed.

The advantages of SATA 6Gb/sec is that it’s a simple interface and it costs less to implement than SAS or FC.  The downside is the loss of performance until 6Gb/sec SATA takes over enterprise storage.

P300’s SSD longevity

I have done many posts discussing SSDs and their longevity or write endurance but this is the first time I have heard any vendor describe drive longevity using “total bytes written” to a drive. Presumably this is a new SSD write endurance standard coming out of JEDEC but I was unable to find any reference to the standard definition.

In any case, the P300 comes in 50GB, 100GB and 200GB capacities and the 200GB drive has a “total bytes written” to the drive capability of 3.5PB with the smaller versions having proportionally lower longevity specs. For the 200GB drive, it’s almost 5 years of 10 complete full drive writes a day, every day of the year.  This seems enough from my perspective to put any SSD longevity considerations to rest.  Although at 255MB/sec sequential writes, the P300 can actually sustain ~10X that rate per day – assuming you never read any data back??

I am sure over provisioning, wear leveling and other techniques were used to attain this longevity. Nonetheless, whatever they did, the SSD market could use more of it.  At this level of SSD longevity the P300 could almost be used in a backup dedupe appliance, if there was need for the performance.

You may recall that Micron and Intel have a joint venture to produce NAND chips.  But the joint venture doesn’t include applications of their NAND technology.  This is why Intel has their own SSD products and why Micron has started to introduce their own products as well.

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So which would you rather see for an SSD longevity specification:

  • Drive MTBF
  • Total bytes written to the drive,
  • Total number of Programl/Erase cycles, or
  • Total drive lifetime, based on some (undefined) predicted write rate per day?

Personally I like total bytes written because it defines the drive reliability in terms everyone can readily understand but what do you think?

CDs and DVDs longevity questioned

DVD-R read/write side (from Wikipedia.org)
DVD-R read/write side (from Wikipedia.org)

In a recent article from BBC on Should you store treasured data on (optical) disk the conclusion was that CDs and DVDs have significantly worse archive life than advertised or even suspected until recently.  The study done by the French National Centre for Scientific Research discovered that the reliability of a few optical disks was just over one year and most “rarely lasted longer than five to 10 years” although they were advertised to last significantly more.

There was not much detail in the BBC article and searching (in English) for the original research yielded nothing pertaining to the topic.   However, the article did say that the centre used accelerated life testing with heat, water vapor and light (standard IT industry practice) to determine point of failure and that products under the same brand had significant archive life variability due to multiple manufacturers.  They also stated that branding the discs might be impacting longevity as well. And that it appeared that the more than seven miles of (probably DVD) data recorded on the discs is deteriating faster than anticipated.

As a result, they suggested that data on optical disks should be copied every two to three years and maybe as time moves on, this can be done less frequently assuming optical disk lifespans improve.  Also important data should be spread across multiple storage formats.

The case for (IT) tape in video archives

Nonetheless, the article did mention that a 52 minute documentary typically requires about 500GB of high definition video to be recorded and at the moment that video is normally stored on data (tape) cassettes and hard drives.  In my experience these (video) tapes were specific to the recording equipment vendor, i.e. Panasonic, Sony, or others and as such, relatively expensive.  But nowadays, this data can also be stored on LTO or other IT tapes.  In contrast to the above, LTO tape has an archival storage life of around 30 years (depending on vendor) and can be had at reasonable cost.

Also, in the past I was aware of a number of TV broadcasters that had an archive of finished broadcasts residing only on DVDs.  They typically took one additional copy of a DVD and stored them both in their desks or file cabinets.  Many of these people will be very surprised when five years down the line, they go to access their archived broadcasts and find that they can no longer be read.  Of course, I have made the same mistake with my family video archive stored on DVDs.

Video archives whether of raw video or finished broadcasts require large capacity, sequentially accessed storage which seems ideal for automated LTO or other magnetic tape storage.  By using IT tape data storage for video archives, one can benefit from technology advances in density and throughput that happen every couple of years, benefit from volume manufacturing available to IT product manufacturers, and benefit from a significantly longer archive life.

Now if I can just find a USB LTO tape drive that works on the Mac for my home videos and family backups I would feel much better, …