Quote:
Originally Posted by DMcCunney
And I'd look seriously at installing an SSD. The usual concern is that SSDs have finite write operations. A cell on an SSD can be written to about 10,000 times. Beyond that, it becomes inaccessible. Current SSDs use firmware that attempts to spread writes evenly over all cells, and the firware also attempts to transparently migrate data on failing cells to good spares and mark the failing cell as bad. In practice, you are likely to upgrade to a new maching lone before you even notice SSD wear.
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Also, please note that there are three kinds of SSD disks:
SLC - Single Level Cell - one memory cell holds one bit - those are SSD disks for fancy servers that you see selling for thousands of dollars (for an SSD not for the entire server) - those have memory cells that can be re-written millions of times
MLC - Multi Level Cell - one memory cell holds two bits so it has to have four voltage levels representing 00, 01, 10, 11 values per cell. Those have hard physical limit of about 7000 writes. You have to use higher voltages than on SLC to be able to be able to distinguish between 4 voltage levels and this physically wears out memory cells. ALL SSD disks sold today have very fancy wear leveling mechanisms that moves data around behind your back, so that all cells are worn out to a similar level, so that one region holding swap file or a temp directory or something doesn't wear out much faster than parts that are only read after OS installation.
TLC - Triple Level Cell - one memory cells holds three bits, EIGHT voltage levels. This has significantly lower number of writes per memory cell. At the time MLC were named nobody expected that one day they would use 8 voltage levels per cell. Otherwise MLCs would have been named DLC.
Many modern "budget" SSDs have TLC, but manufacturers do not like to advertise the fact that the disk uses TLC instead of MLC and has much lower wear reserve. You usually have to google extensively to identify whether the SSD has MLC or TLC.
One of most popular models from Samsung - 840 Evo had a big scandal some time ago - this was one of first popular drives to use TLC and it turned out that when the data sits on the disk for half a year untouched the read speed is extremely slow - due to voltage drop. They still haven't solved that problem. There *is* a firmware update available for those disks but I suspect that they just re-write the data periodically, further increasing the wear of the disk.
The situation is further complicated by the fact that the increased density of modern silicon makes the memory cells less resistant to wear.
Recently there were vertical NANDs introduced by Samsung and they have insanely high warranties and guaranteed writes. Again, those come in MLC and TLC variety, with MLC being cheaper and less wear resistant.
I have purchased a huge 1TB SSD for this Linux machine.
In the last 516 days I have written 4559GB to the disk - overwriting it 4.5 times (out of several several thousand that are physically possible and several hundred that manufacturer guarantees).
I use the disk quite extensively, with a large Calibre Library, some development ...
The only thing I have done in this Linux is
- installed plenty of RAM and set swappiness in Kernel parameters to a low value, so the kernel does not start to use swap preemptively, before it really needs it
- set noatime parameter in fstab, so that the filesystem doesn't set time when you read the file - this would needlessly increase writes and for normal home desktop use the access time - atime parameter is never used anyway.
- made sure fstrim is working automatically. You have to TRIM the SSD periodically to free up cells after delete of data. SSD has to erase the whole block of data at once when you change something, and reclaiming this space as you go (when you run out of available cells) is very time consuming. Please note that modern distros should have this working out-of-box
I was very reluctant to purchase the SSD, because I need to work with a very large number of small files (in Calibre, development and other scenarios) and I worried about how long the SSD would last. BLOODY expensive SSD, mind you ;-). Yet, this is scenario where SSD really shines. If you imagine that each memory cell has a very limited lifetime of several thousand writes you *have* to be anxious, especially if you know how many files are written when you do a bulk rename in Calibre or dabble in software development with some projects that have thousands of files that need to be updated frequently. Even Calibre itself is some 200MB and gets updated once a week. Virtual machines can also cause lots of writes to the image file.
After the SSD purchase I wrote a script that queries SMART data on disk and prints how much data I write daily and over the lifetime of the disk. I see that even with intensive use the disk will be obsoleted *long* before it is written to death, even if it was a dreaded TLC ;-)
Quote:
Originally Posted by DMcCunney
Last but not least, pay attention to what video is offered on the machine you get. Will it be adequate for your needs, or will you want to add a video card? Will the video card you use be supported by Linux? Is there a manufacture's driver for Linux, or are you limited to existing Linux support for the card? You didn't mention details on what sort of video editing you wanted to do, but you need decent video on the machine to support it.
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I personally prefer the built-in Intel graphics. It is adequate for my needs and this way I have least amount of hassle with graphics drivers and tinkering with graphics system