On 2016-05-19 17:01, Kai Krakow wrote:
Am Thu, 19 May 2016 14:51:01 -0400
schrieb "Austin S. Hemmelgarn" <ahferro...@gmail.com>:
For a point of reference, I've
got a pair of 250GB Crucial MX100's (they cost less than 0.50 USD per
GB when I got them and provide essentially the same power-loss
protections that the high end Intel SSD's do) which have seen more
than 2.5TB of data writes over their lifetime, combined from at least
three different filesystem formats (BTRFS, FAT32, and ext4), swap
space, and LVM management, and the wear-leveling indicator on each
still says they have 100% life remaining, and the similar 500GB one I
just recently upgraded in my laptop had seen over 50TB of writes and
was still saying 95% life remaining (and had been for months).
Correction, I hadn't checked recently, the 250G ones have seen about
6.336TB of writes (I hadn't checked for multiple months), and report 90%
remaining life, with about 240 days of power-on time. This overall
equates to about 775MBs of writes per-hour, and assuming similar write
rates for the remaining life of the SSD, I can still expect roughly 9
years of service from these, which means about 10 years of life given my
usage, which is well beyond what I typically get from a traditional hard
disk for the same price, and far exceeds the typical usable life of most
desktops, laptops, and even some workstation computers.
And you have to also keep in mind, this 775MB/hour of writes is coming
from a system that is running:
* BOINC distributed computing applications (regularly downloading big
files, and almost constantly writing data)
* Dropbox
* Software builds for almost a dozen different systems (I use Gentoo, so
_everything_ is built locally)
* Regression testing for BTRFS
* Basic network services (DHCP, DNS, and similar things)
* A tor entry node
* A local mail server (store and forward only, I just use it for
monitoring messages)
And all of that (except the BTRFS regression testing) is running 24/7,
and that's just the local VM's, and doesn't include the file sharing or
SAN services. Root filesystems for all of these VM's are all on the
SSD's, as is the host's root filesystem and swap partition, and many of
the data partitions. And I haven't really done any write optimization,
and it's still less than 1GB/hour of writes to the SSD. The typical
user (including many types of server systems) will be writing much less
than that most of the time.
The smaller Crucials are much worse at that: The MX100 128GB version I
had was specified for 85TB writes which I hit after about 12 months (97%
lifetime used according to smartctl) due to excessive write patterns.
I'm not sure how long it would have lasted but I decided to swap it for
a Samsung 500GB drive, and reconfigure my system for much less write
patterns.
What should I say: I liked the Crucial more, first: It has an easy
lifetime counter in smartctl, Samsung doesn't. And it had powerloss
protection which Samsung doesn't explicitly mention (tho I think it has
it).
At least, according to endurance tests, my Samsung SSD should take
about 1 PB of writes. I've already written 7 TB if I can trust the
smartctl raw value.
But I think you cannot compare specification values to a real endurance
test... I think it says 150TBW for 500GB 850 EVO.
The point was more that wear out is less of an issue for a lot of people
than many individuals make it out to be, not me trying to make Crucial
sound like an amazing brand. Yes, one of the Crucial MX100's may not
last long as a Samsung EVO in a busy mail server or something similar,
but for a majority of people, they will probably outlast the usefulness
of the computer.
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