Hi Mick,
On Sun, Oct 11, 2020 at 05:45:45PM +0100, mick crane wrote:
Got a PC that has SSD and a HDD. I see that you are supposed to avoid
writes
to SSD for longevity.
Flash write endurance has come on leaps and bounds over the last
decade to the point where most people don't have to worry about
this.
You can look at "tune2fs -l" output or at SMART attributes to see
how much has been written to your current filesystems / devices over
their life times, to see how your use case matches up against the
write endurance advertised for your SSD.
I wouldn't recommend taking any special measures unless you have
some doubt that the SSD endurance is up to it.
With only a single SSD and a single HDD I'd rate device failure from
other problems as a higher risk than wearing out the SSD.
Is it a matter of putting entries in fstab for /swap /var /home to
suitably
formatted partitions on HDD ?
If you still think you will have a problem then yes, that is one way
to go. Another is to leave some percentage of the SSD unpartitioned
and never used. That will increase its write endurance.
[ Leaving aside the fact that if I were doing this I'd have an extra
storage device for redundancy… ]
If I were in your position and still had concerns about write
endurance I'd probably put everything in LVM with a volume group on
the SSD and a volume group on the HDD. I'd then use separate logical
volumes for the filesystems that got a lot of writes. The use of LVM
like this would allow me to change my mind later and move LVs
between the SSD and HDD while the machine is online.
Plus any time you are thinking of doing multiple filesystems, LVM is
a good bet.
Plus you might be using LVM anyway for encryption.
But again I can't emphasise enough how you are probably over thinking
write endurance.
Cheers,
Andy