Thats some interesting information on SSD's :-) On Mon, Feb 29, 2016 at 10:18 AM, Carruth, Rusty wrote: > There are a few secrets for longevity on an SSD. > > > > One way, as Stephen notes, is reducing your writes (trim also helps with > this, by the way). > > > > Another way is to not use the whole drive. That is, don’t fill it up. > That effectively gives you more ‘spares’ so that the drive *may* be able > to reduce the ‘write amplification’ a little, and also perhaps have > somewhere to write stuff even if the number of ‘bad blocks’ (for a fuller > drive) would make the drive unusable. > > > > Huh? What is ‘write amplification’? Well, it’s a ‘feature’ of SSDs > caused (primarily) by the fact that the SSD is not arranged as LBAs > (sectors). The smallest amount of the flash that can be erased is an erase > block, which can be 1Mbit or more! And the smallest amount you can write > is a ‘page’. (Pages tend to be 4k Bytes or more) > > > > And you cannot write to an un-erased area – that is, once written a ‘page’ > in the erase block, you cannot write it again without erasing first. > > > > So, imagine you are filling up an erase block with sectors (512 bytes). > Now lets say you have sectors 1-20 and 2000-2010 in it, and now its full. > Now, you change what’s in sector 2000 and write it back. > > > > The drive CANNOT write it back in that erase block (unless there is space > at the end of the erase block, but then I just said it was full ;-)). > > > > So, it has to ‘do something’ with that new sector. Sometimes it has to > COPY the ENTIRE erase block into a NEW erase block, inserting the new > sector’s worth of data. > > > > So a single 512-byte write resulted in 100Kbytes (or whatever) being > written to the flash! > > > > So, a single write was amplified into what looked more like 200 writes! > Ouch! Welcome to write amplification! > > > > (And it gets even worse if there aren’t enough ‘spare’ (already erased but > not written) blocks – you may have to copy other full or partially-full > blocks around also!) > > > > For some drives, they can do a better job if they have more spare blocks > around – so, if your drive isn’t full you’ve got more spares (if the drive > firmware views them that way). In addition, you may be able to run longer > by having more bad blocks but not enough to have no non-bad blocks for the > amount of data you have on the drive. > > > > Now, a little bit more info about SSDs, followed by 2 disclaimers. > > > > SSDs are made up of Flash. Flash comes in at least 3 varieties: > > > > SLC – aka ‘Single Level Cell’, which means that you only store 1 bit per > transistor cell > > MLC – aka ‘Multi Level Cell’, which means you store 2 bits per transistor > cell. > > TLC – aka ‘Triple Level Cell’, which means (you probably guessed it) that > you store 3 bits per transistor cell. > > > > (As a very scary fact, my understanding is that a transistor cell holds, > at maximum, about 100 electrons. So, for SLC there are 2 values > represented by 0 to 100 electrons. (you can pretend that under 50 electrons > means a zero and above that means a 1 and not be too far off the mark). > For MLC, 4 values are represented by those same 100 electrons. For TLC, > that’s 8 values, or a difference of only 100/8 electrons per different > ‘value’!) > > > > Now, the other critical thing is that Flash manufacturers ‘guarantee’ a > maximum error rate across the entire chip until that chip reaches a certain > number of ‘program/erase’ cycles (as described above). It is true that > some chips will do MUCH better (We’ve seen, in our testing, an SLC chip run > 1million P/E cycles before becoming unusable – when the factory only gives > 100,000). But in any case, here’s my understanding of the PE numbers for > the different technologies: > > > > SLC: 100,000 > > MLC: 10,000 > > TLC: 1,000 (I think – its been a while since anybody mentioned this > number to me) > > > > Which speaks directly to Stephen’s comment about number of PE cycles (ok, > he didn’t say PE, but that’s what he is actually referring to J). > > > > However, you probably don’t want to seriously consider rushing out and > buying SLC drives – they cost MUCH more than MLC drives (like, 10 to 100 > times more). Just back up early, back up often (as you should do for ANY > primary storage device!!!) > > > > > > Disclaimer 1 – I work for a company that makes SSDs. The above is NOT > professional advice. See a real SSD shrink for professional advice. > > > > Disclaimer 2 – Due to our IT department’s method of handling email, at > this time I can RECEIVE PLUG emails, but I cannot REPLY to them (and have > them seen). So I’m BCC’ing people and hoping they reply all, so that you > can see this. Otherwise, only 2 folks will read it. > > > > Rusty > > > > *From:* plug-discuss-bounces@lists.phxlinux.org [mailto: > plug-discuss-bounces@lists.phxlinux.org] *On Behalf Of *Stephen Partington > *Sent:* Monday, February 29, 2016 9:45 AM > *To:* Main PLUG discussion list > *Subject:* Re: Upgrade old laptop with SSD > > > > The lifespan will depend entirely on the number of Writes the drive will > incur. The first thing you want to do once the Os is installed is to reduce > this. If you have enough ram and are comfortable with nos wap go for it. If > you want the backup i would suggest pushing swappiness all the way over so > that it is used only if there is no ram. > > > > Most SSD's will give you a 3 year warranty. Samsung with their Evo 850 > drives and the new vnand are offering 5 year warranty. (they are also > wicked fast). > > > > That being said. with minimal writes I have seen older SSD's last for much > longer than their supplied 3 year warranty (I have one that is pushing 6 > right now). > > > > With an SSD the general user experience will be pretty good, but Anytime > you run updates it will still crawl, regardless fo the SSD :-) > > > > On Mon, Feb 29, 2016 at 8:49 AM, Keith Smith > wrote: > > > > Hi, > > I have an older laptop. Not sure when I bought it. I'm thinking I bought > it before 2009, however the CPU is an AMD 3300M which according to what I > am reading was not in production until 2011. It has 4G of RAM and a 500GB > HD. It's running Win7, which is a little slow. > > I was thinking of replacing the HD with an SSD and potentially making it > into a "Chromebook".... (Thunderbird/Libre Office/ Chrome Browser) I'm > reading the SSD's are 10x faster than the HD. There has been prior > discussions about breathing life into old hardware by replacing the HD with > SSD and installing Linux (now we are on topic). > > Initially I was thinking a small SSD since I will probably never use this > laptop in production... But you never know. If these mods work out I might > dual boot it - Win7 / Mint 17 KDE. > > Newegg is selling a 240G Kingston SSD for $65 which is probably way more > storage than I would ever need. > http://www.newegg.com/Product/Product.aspx?Item=N82E16820721108 > > What type of lifespan should I expect for an SSD with moderate usage? > > Anything specific I should be looking at? > > Thank you so much for your help!! > > -- > Keith Smith > --------------------------------------------------- > PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org > To subscribe, unsubscribe, or to change your mail settings: > http://lists.phxlinux.org/mailman/listinfo/plug-discuss > > > > > > -- > > A mouse trap, placed on top of your alarm clock, will prevent you from > rolling over and going back to sleep after you hit the snooze button. > > Stephen > -- A mouse trap, placed on top of your alarm clock, will prevent you from rolling over and going back to sleep after you hit the snooze button. Stephen