Re: [GENERAL] PostgreSQL on eMMC - Corrupt file system

Am 10.02.2017 um 09:16 schrieb Mark Morgan Lloyd:
> On 09/02/17 23:00, Christoph Moench-Tegeder wrote:
>> ## Thomas Güttler (guettliml@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
internalSD-Card without problems, but the one Odroid which runs an eMMC card failed a few weeks ago. Second, a useful
precautionis to put stuff which will be updated on an external device, although the same longevity concerns apply if
it'sFlash-based. Third, experience here suggests that reliability /might/ be improved if you fully zero a device before
partitioningit 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/