Re: Linux LVM software raid, and SAN question.

Kyle Schmitt wrote:

Software raid to mirror the luns from both sans, and use static
partitions?
Software raid, then LVM ontop of it?
LVM to mirror and handle the whole damned thing?
PowerPath for multipathing, or using the multipathing the kernel
provides?

The particular instance I'm dealing with is a database server that
will have two HBAs, each connected to a different SAN, which is
mirrored from the linux side.  While there are several ways I know how
to set it up, I'm unsure as to which will really be the best way (not
necessarily easiest) to do it.

Thanks
--Kyle

1
=

Well just have read all the reply's you have got so far, let me suggest.
http://www.symantec.com/business/theme.jsp?themeid=sfbasic

And if you can do with max 4 volumes to be mirrored; go for it - Replacing
the ext3 (or what ever) with vxfs and LWM with vxvm [remember to enable
Dirty Read Logs (fast resync after crash)].

LWN in Linux is OK, but for your setup I would suggest this Software because
is has more "guarantees", in fail situations.

Simply think (based on 14 years in the IT business as administrator) crash
situations is better handled by this commercial product.

Faulty PSU's (or even worse, much worse, partly faulty PSU's - PSU's that
don't die) I think is cause to a lot of errors in software based RAID
solutions. RAID much much better done in hardware!!

2
=
Depending on your database, let the database replicate itself to another
database instance (on the other disk system). No need at all for software
in the OS to complicate things.


/Lars H.


.

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