Re: Can I software RAID 1 two external (USB) hard drives?

On Jan 25, 8:45 pm, an...@xxxxxxxxxxxxxxxxxxxxxxxxxx (Anton Ertl)
wrote:
Baron Samedi <Papa.Legba....@xxxxxxxxx> writes:
 I can't afford an external housing with built in RAID, so will
accept software based RAID.

I have an external housing, connected by USB, containing two identical
hard drives.

Can I make them appear as one, by using RAID 1 (mirror) in software?

If you see each drive as a separate device (which is probably the
case), then yes, you can.

If so, how?

With mdadm, or with the installation software of your distribution.
You will typically partition the drives in the same fashion, and then
combine each pair of partitions into a RAID1.

Note that with this setup, performance won't be great, especially for
writes: On writes all the data has to go through the USB twice, and
the fastest transfer rates I have seen through USB are around 30MB/s.

- anton
--
M. Anton Ertl                    Some things have to be seen to be believed
an...@xxxxxxxxxxxxxxxxxxxxxxxxxx Most things have to be believed to be seenhttp://www.complang.tuwien.ac.at/anton/home.html


Thanks for the info, that sounds like what I want.

I'm not too concerned about slow write, as this is mostly photos, with
the odd movie and maybe a little MP3. Wrtie is only once, intially,
it's not like they are data fiels that are regularly opened and
updated.
.

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