Am 10.02.2017 um 09:16 schrieb Mark Morgan Lloyd: > On 09/02/17 23:00, Christoph Moench-Tegeder wrote: >> ## Thomas Güttler (guettl...@thomas-guettler.de): >> >>> Is running linux with postgres on eMMC a bad idea in general? >> >> I'd say that running anything with a read-write load on eMMC will >> end in pieces. It's ok to occasionally write something, but a mixed >> load is not really what these things were designed for. The wear >> leveling can be quite basic, you never know when it's gonna happen >> (i.e. sudden power down can kill your filesystem - that's why disabling >> journaling is not a very great idea), and if your device is "mostly >> full" anyways, the wear leveling has not much space to redirect the >> writes to. Remember that some of those chips are sold mostly by >> price - that is, the hobbyist "embedded" devices get the cheapest >> chips. A safer bet would be adding an external storage; some >> 64GB SATA SSDs are available for less than 50€ (perhaps it's better >> not to go for the cheapest ones here, too). > > I agree, but three additional comments. First, we've got a fair number of > RPis running their root filesystems on the internal SD-Card without problems, > but the one Odroid which runs an eMMC card failed a few weeks ago. Second, a > useful precaution is to put stuff which will be updated on an external > device, although the same longevity concerns apply if it's Flash-based. > Third, experience here suggests that reliability /might/ be improved if you > fully zero a device before partitioning it to make absolutely sure that the > internal controller has touched every block.
to fully zero the device ... sounds reasonable. Thank you for sharing your knowledge. BTW, I moved postgres and /var/log to an external disc. I removed swap from eMMC and use tmpfs for /tmp. Since these changes, I had no failure any more. In this case it is just a small server for my personal environment. But still I have a bad feeling ... Regards, Thomas Güttler -- http://www.thomas-guettler.de/ -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
