On Wed, Feb 08, 2017 at 11:20:32PM -0500, Julie Marchant wrote: > On 02/08/2017 07:15 PM, Julie Marchant wrote: > > Mike, if that article is accurate, the study doesn't contradict what I > > said: > > > >> None of the drives in the study came anywhere near their write limits, > >> even the 3,000 writes specified for the MLC drives > > I wrote this while I was at work on my break, so now that I have more > time, let me elaborate. > > Supposedly, in all cases tested, none of the SSDs were written to > anywhere near enough times to cause substantial wear. It is mentioned in > this article summarizing it that even 3,000 writes were not reached. > Most flash media can sustain at least tens of thousands of writes, so if > not even 3,000 writes were reached, it makes sense that none of the SSDs > tested failed. > > However, it doesn't follow that this kind of wear is insignificant for > all flash memory. In particular: > > * SSDs tend to be larger than SD cards, so they're not going to wear out > as fast unless the entirety of the space is being used and constantly > changed. > * The firmware of SSDs may be different from the firmware of SD cards. > For that matter, the firmware of SSDs may be different from the firmware > of other SSDs. Don't underestimate the power of wear leveling. > > It still holds true that every change to any flash memory brings it > closer to the end of its life. It's just that other factors can do this, > too, and in some cases (e.g. SSDs) it may mean that the write cycle > limit is less important in practice.
A test we did for our systems is to constantly (re)write and sync a large random file for many cycles (enough to simulate several years of normal operation), and generally encountered hardly any faults. Feel free to test this yourself. -- Tzafrir Cohen | tzaf...@jabber.org | VIM is http://tzafrir.org.il | | a Mutt's tzaf...@cohens.org.il | | best tzaf...@debian.org | | friend _______________________________________________ arm-netbook mailing list arm-netbook@lists.phcomp.co.uk http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to arm-netb...@files.phcomp.co.uk
