Re: errors on shadow sets and their members

From: Lee Mah (lytmah_at_telusplanet.net)
Date: 04/25/04 

Date: Sun, 25 Apr 2004 21:25:05 GMT

 From my experience with shadowing, these have been my observations:

Don't bother looking for errors on the shadow (DSA) devices. They won't
log any.
The errors will show on the nodes which are doing, or have done,
MSCP-serving of the troubled device.
For example,

$ mc sysman
SYSMAN> set env/cluster
%SYSMAN-I-ENV, current command environment:
        Clusterwide on local cluster
        Username Z99999 will be used on nonlocal nodes
 
SYSMAN> do show dev DSA123:
%SYSMAN-I-OUTPUT, command execution on node C
Device Device Error Volume Free
Trans Mnt
 Name Status Count Label Blocks
Count Cnt
DSA123: Mounted 0 SS123 12466386
256 4
$2$DUA569: (A) ShadowSetMember 0 (member of DSA123:)
$2$DUA223: (HSJM22) ShadowSetMember 12 (member of DSA123:)

%SYSMAN-I-OUTPUT, command execution on node A
Device Device Error Volume Free
Trans Mnt
 Name Status Count Label Blocks
Count Cnt
DSA123: Mounted 0 SS123 12466422
235 4
$2$DUA569: (HSJM11) ShadowSetMember 0 (member of DSA123:)
$2$DUA223: (C) ShadowSetMember 0 (member of DSA123:)

%SYSMAN-I-OUTPUT, command execution on node D
Device Device Error Volume Free
Trans Mnt
 Name Status Count Label Blocks
Count Cnt
DSA123: Mounted 0 SS123 12466422
193 4
$2$DUA569: (A) ShadowSetMember 0 (member of DSA123:)
$2$DUA223: (HSJM22) ShadowSetMember 6 (member of DSA123:)

%SYSMAN-I-OUTPUT, command execution on node B
Device Device Error Volume Free
Trans Mnt
 Name Status Count Label Blocks
Count Cnt
DSA123: Mounted 0 SS123 12466422
173 4
$2$DUA123: (HSJM11) ShadowSetMember 0 (member of DSA123:)
$2$DUA223: (D) ShadowSetMember 0 (member of DSA123:)

Phillip Helbig---remove CLOTHES to reply wrote:

>I've rearranged some hardware in my hobbyist cluster. In one BA353
>there is an RZ26 which I can't remove, so I'm "forced" to use it. It is
>a member of a shadow set (the other member is on another node). During
>SHADOW MERGE or COPY operations, it collects 10--15 errors, but only on
>the node it has a direct connection to, not to all the other nodes, to
>which it is MSCP served. The shadow set is mounted by all nodes and
>shows no errors.
>
>What does this mean?
>
>Presumably, since the shadow set itself has no errors, and neither does
>the other member, as long as the good member or both members are
>available, there will be no problems. What happens if the good member
>goes, leaving only the member with the errors on the node it is directly
>connected to? Will this result in errors on the shadow set?
>
>Are the errors likely to be physical problems with the disk, or could
>they be due to a software problem or a configuration problem (say, too
>many packet collions on the LAN during the MERGE operation)?
>
>
>

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