[wellylug] Linux (IDE) software RAID advice, please...

[Ewen McNeill]

In message <20041007212712.17026.qmail at web12210.mail.yahoo.com>, Wood Brent writes:
>I want to maximise read performance using two drives under Linux software RAID.
>Streaming large files (up to several Gb ea) & Postgres databases.
>[....]
>I don't know if Linux software RAID1 will read from both drives or not. 

I believe it will.

http://www.tldp.org/HOWTO/Software-RAID-HOWTO-1.html#ss1.4

also implies that it will.  Write performance on RAID-1 can be a little
so-so (due to the need to write to two disks, and worse if there are 
limitations on overlapping I/O such as with IDE), but read performance 
should be better than for a single drive particularly if they're
arranged so as to maximise the opportunity for overlapped I/O.

There are also some relatively inexpensive hardware RAID cards that are 
well supported under Linux (3Ware, Adaptec, etc for IDE, plenty of
choices for SCSI).

Ewen