Am 10.02.2017 um 09:16 schrieb Mark Morgan Lloyd: > On 09/02/17 23:00, Christoph Moench-Tegeder wrote: >> ## Thomas Güttler (guettliml@xxxxxxxxxxxxxxxxxx): >> >>> 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@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
