On Sunday 24 June 2018 06:15:24 Luke Kenneth Casson Leighton wrote: > On Sat, Jun 23, 2018 at 4:15 PM, Gene Heskett <ghesk...@shentel.net> wrote: > >> So when you first plug in a flash device, only a few megabytes are > >> actually available for writing, and the controller is busy running > >> self test routines on the rest. Any writes to the untested parts of > >> the flash get queued behind the testing so will be quite slow. Most > >> users would not notice an effect, especially with SD cards in > >> digital cameras because they are powered all the time and only > >> filled gradually. > > > > Sounds plausible, but you'd think they'd want to test it just to > > stop the shipment of bad product. > > pffh, naah. you can't do tests on flash without actually risking > damaging it. damage means reduced life. reduced life means less > confidence from the customer as its capacity is less than what it's > supposed to be. much better to ship out untested product and let > amazon and other sales front(s) deal with complaints and returns. > > firmware on low-cost (and newly-designed unusual) SSDs is extremely > dodgy. one of the drives that i tested literally crawled to an > absolute stand-still after a certain sustained amount of parallel > writing (from different processes). the article went out on slashdot > and i was given some advice about it: stop the parallel write > queueing. there's a linux kernel parameter somewhere for it... i > didn't get to try it out unfortunately. > > this was after OCZ had been caught switching on a firmware #define > which they had been TOLD under no circumstances to enable as it causes > data corruption (they wanted to be "faster" than the competition). > the data corruption was so bad it actually in some cases overwrote the > actual firmware *on the drive*, meaning that the SSD was no longer... > an SSD. > > the only reasonably-priced SSDs i trust now are the intel s35xx > series. other drives such as the toshibas which are also supposed to > have supercapacitors for "enhanced power loss protection", the > supercapacitors simply aren't large enough, so a sustained series of > writes above a certain threshold speed, pull the power and there's not > enough in the supercapacitors to cover the time it takes to save the > cached data. > > only the intel s35xx series has had the work put into it, > technically, to do the job *at a reasonable price*. i ran a 4-day > test writing several terabytes of data, the power was randomly pulled > at between 7 and 25 second intervals, for a total of six and a half > THOUSAND times, and *not a single byte* was lost. which is deeply > impressive. > > the s37xx series is by a different team and they use the fuckwit > marvel "consumer" chipset that's so troublesome in kingston, crucial > and other SSDs. > > really not being funny or anything: if you care about your data > (*and* your wallet) just don't buy anything other than intel s35xx > series SSDs. of course if you have over $10k to spend there are > plenty of data-centre quality SSDs. > > l.
I will try to remember that s35xx intel. Unforch, that search at newegg comes back empty today. So far, and I've had a couple of 60GB adata or SP ssd's in use here for several months with no problems, on sale for about a 44 dollar bill each from newegg, figured I'd get my feet wet since with amanda I can do a bare metal revert back to spinning rust should it blow up. So far, so good. The 3rd one I just put on the pi, an SP 60GB thats now 24 bucks, with a $10 usb-3<->sata adapter plugged into a usb-2 port on the pi, seems to be ok so far. Yeah, that faint knocking sound is real but my knuckles are getting tender. :) If it dies while building a kernel on it, thats the price we pay for experience as I totalled a tiny spinning rust seagate 1T with a usb-3 cable sticking out of it. Spinning hours maybe 1500 when it signed off, $50 bucks from Wallies. Running off the rock64 usb-3 port. Worked very well, with speeds in the 350 meg a second region, when it worked. It does seem to be the direction to get used to. -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene>
