(OT) Questions About SSDs for a Laptop

[Michael Butash]

On 09/02/2014 10:23 AM, Mark Phillips wrote:
> I am looking at a new Linux laptop, and I have the option of a mSata 
> SSD drive or a conventional drive. I am considering a 1 TB Samsung 840 
> EVO mSata SSD for the OS and all my partitions.
>
> 1. Are there any reasons not to use a SSD for the full disk, as 
> opposed to just for the OS? Other than saving money, as a small SSD 
> would cost a lot less!
None I can think of, I do this with mine.  I slice out root, var, 
var/log, usr, and home to lvm's, usually adding another dump slice under 
/mnt for "everything else" including vm images and such across the whole 
disk.  I do not however provision all the vg space, reserving it for 
another slice, lvextending, etc case I run out of space elsewhere.
>
> 2. I have seen recommendations on the net to backup the drive to a 
> spinning drive. The laptop has a couple of bays, so I could put a back 
> up drive in one of the bays. Does this make sense, or have SSDs 
> matured enough that they will last like a spinning drive?
You'll want to do the optimizations still.  I have a pretty complex 
setup I have to build at an initrd usually outside of installers, 
aligning blocks/chunks across disparate filesystems from mdraid, 
cryptsetup, lvm, to ext4.  I don't use trim (cryptsetup 
vulnerabilities), but it's possible to do full-stack traversal like that 
apparently.

See also: 
http://blog.neutrino.es/2013/howto-properly-activate-trim-for-your-ssd-on-linux-fstrim-lvm-and-dmcrypt/
>
> 3. Anything else I should be aware of when moving to the world of SSDs?
Yes, they die.  Often in my experience.  I never NOT raid1 them now.  My 
first I thought it'd be cool to raid0, and holy crap it was fast.  Then 
one (thus all my data) died after 2 months.  Raid1 ftw from here out.  I 
have way too much proprietary data to not keep it resilient (mdadm), 
keep it secure (cryptsetup), and keep it flexible (lvm).

I've used them from the first gen sandforce and micron chips, they all 
die at some point.  Most lasting recently was my old adata sandforce2+ 
drives, but one would randomly fall out of raid, but this could have 
also been my mobo sucking (intel p65, with the oob crap southbridge).

Along the way I perfected my install to the point the ssd's keep lasting 
longer, so I like to think it's that, but really not sure if hw is 
getting better, or I'm better at not slaughtering them with io.

I'm currently using 2x mx100 512gb ssd's in my desktop and 2x samsung 
840 512gb msata's in my dell e7420 that knock on wood has been great, 
both raid1 only.  I've never not been able to recover data off a raid1 
config with linux when one fails.

Happy to share my setup steps, latest to do this with mint, but sorta 
works with ubuntu other than their installers being terrible about 
dealing with me shifting the fs about under it.  I gave up doing this 
with 14.04, they crippled it entirely for this sort of setup.
>
> Thanks,
>
> Mark
>
>
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