Re: Software raid0 will crash the file-system, when each disk is5TB

From: Bill Davidsen
Date: Wed May 16 2007 - 13:27:55 EST


Jeff Zheng wrote:
Here is the information of the created raid0. Hope it is enough.

If I read this correctly, the problem is with JFS rather than RAID? Have you tried not mounting the JFS filesystem but just starting the array which crashes, so you can read bits of it, etc, and verify that the array itself is working?

And can you run an fsck on the filesystem, if that makes sense? I assume you got to actually write a f/s at one time, and I've never used JFS under Linux. I spent five+ years using it on AIX, though, complex but robust.
The crashing one:
md: bind<sdd>
md: bind<sde>
md: raid0 personality registered for level 0
md0: setting max_sectors to 4096, segment boundary to 1048575
raid0: looking at sde
raid0: comparing sde(5859284992) with sde(5859284992)
raid0: END
raid0: ==> UNIQUE
raid0: 1 zones
raid0: looking at sdd
raid0: comparing sdd(5859284992) with sde(5859284992)
raid0: EQUAL
raid0: FINAL 1 zones
raid0: done.
raid0 : md_size is 11718569984 blocks.
raid0 : conf->hash_spacing is 11718569984 blocks.
raid0 : nb_zone is 2.
raid0 : Allocating 8 bytes for hash.
JFS: nTxBlock = 8192, nTxLock = 65536

The working one:
md: bind<sde>
md: bind<sdf>
md: bind<sdg>
md: bind<sdd>
md0: setting max_sectors to 4096, segment boundary to 1048575
raid0: looking at sdd
raid0: comparing sdd(2929641472) with sdd(2929641472)
raid0: END
raid0: ==> UNIQUE
raid0: 1 zones
raid0: looking at sdg
raid0: comparing sdg(2929641472) with sdd(2929641472)
raid0: EQUAL
raid0: looking at sdf
raid0: comparing sdf(2929641472) with sdd(2929641472)
raid0: EQUAL
raid0: looking at sde
raid0: comparing sde(2929641472) with sdd(2929641472)
raid0: EQUAL
raid0: FINAL 1 zones
raid0: done.
raid0 : md_size is 11718565888 blocks.
raid0 : conf->hash_spacing is 11718565888 blocks.
raid0 : nb_zone is 2.
raid0 : Allocating 8 bytes for hash.
JFS: nTxBlock = 8192, nTxLock = 65536

-----Original Message-----
From: Neil Brown [mailto:neilb@xxxxxxx] Sent: Wednesday, 16 May 2007 12:04 p.m.
To: Michal Piotrowski
Cc: Jeff Zheng; Ingo Molnar; linux-raid@xxxxxxxxxxxxxxx;
linux-kernel@xxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx
Subject: Re: Software raid0 will crash the file-system, when each disk
is 5TB

On Wednesday May 16, michal.k.k.piotrowski@xxxxxxxxx wrote:
Anybody have a clue?


No...
When a raid0 array is assemble, quite a lot of message get printed
about number of zones and hash_spacing etc. Can you collect and post
those. Both for the failing case (2*5.5T) and the working case
(4*2.55T) is possible.


--
bill davidsen <davidsen@xxxxxxx>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979

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