i am wondering how to best setup the storage, putting most emphasis on longevity/stability, mainly regarding failure of the storage medium.
we are forced to at least boot from MicroSD card, but they are known to be especially bad to be used as main storage in a typical scenario of a server: lots of small reads and writes, all the time.
one can try to work against that by trying to get a MicroSD card that is optimized for such tasks and longevity, but (for me) it is hard to get even a rough feeling about how much this really would improve the situation.
therefore, i would like to know how to best setup my system. for example, i heard these ideas so far: using a read-only partition on the SD to boot and a read-write one on a USB stick. combine them somehow with UnionFS, and making additional backups on a remote site. also, turning off logging, or trying to use a ram-disc for the common log directories, and compiling a custom debian image with only the bare minimum packages one requires. using ext2 as file system, because it has no journaling, which saves I/O operations. using exotic file-systems which fare better for SD, ...
is there already good info out there about all this?
i currently have as hardware:
* 16GB MicroSD (MLC Flash, supposedly high endurance)
* 8GB USB memory stick (MLC Flash)
connect a sata harddisk or ssd
i'd prefer to avoid that because of required space, noise, heat production and especially power consumption.
but let's say it is an option: could i boot from SATA directly and skip the MicroSD completely?
a short forum sweep suggest that it is possible, with some fiddling.
or is there some setup that would let the SATA disc sleep for most of the time, and use only flash, except for a few minutes a day for syncing?
i just saw on a blog-post... most SATA drives require 5V + 12V, and i would need a special one that works with only 5V? or otherwise supply power in an alternative way, not through the olinuxino?
2.5" Sata drives only need 5V, and the A20 micro board supplies that. Olimex even offers a cable to connect a 2.5" drive with data and power. However, the sata drive is not part of the boot sequence in the A20 chip. So, the best method, I think, and one that is used by many, is to use the SDCard as a read-only boot device that simply loads U-Boot and then uses the sata drive for reading and writing. Power use is not a problem.
There are several how-to's on the internet. Google 'A20 micro sata boot'.
Read this one first: https://wiki.debian.org/InstallingDebianOn/Allwinner