On 4/5/2014 8:13 AM, David Boreham wrote:
> On 4/4/2014 5:29 PM, Lists wrote:
>> So, spend the money and get the enterprise class SSDs. They have come
>> down considerably in price over the last year or so. Although on
>> paper the Intel Enterprise SSDs tend to trail the performance numbers
>> of the leading consumer drives, they have wear characteristics that
>> mean you can trust them as much as you can any other drive for years,
>> and they still leave spinning rust far, far behind.
>
> Another issue to bear in mind is that SSD performance may not be
> consistent over time. This is because the software on the drive that
> manages where data lives in the NAND chips has to perform operations
> similar to garbage collection. Drive performance may slowly decrease
> over the lifetime of the drive, or worse : Consumer drives may be
> designed such that this GC-like activity is expected to take place
> "when the drive is idle", which it may well be for much of the time,
> in a laptop. However, in a server subject to a constant load, there
> may never be "idle time". As a result the drive may all of a sudden
> decide to stop processing host I/O operations while it reshuffles its
> blocks. Enterprise drives are designed to address this problem and are
> specified for longevity under a constant high workload. Performance is
> similarly specified over worst-case lifetime conditions (which could
> explain why consumer drives appear to be faster, at least initially).
My experience has been, consumer SSDs used in a high usage desktop type
environment are about twice as slow after a year as they were brand
new. I note my current desktop system has written 15TB total onto my
250GB drive after about 16 months. The SMART wear leveling count
suggests the drive has 91% of its useful life left.
--
john r pierce 37N 122W
somewhere on the middle of the left coast
