[rescue] Drive Replacement Question

[Brian Deloria]

I had also read that I may have had to use the metaclear and metainit
command.  I don't believe that this would have solved my problem plus I was
fairly unclear on the syntax and usage and was quite concerned I'd kill the
mirror.  It seemed like the examples wanted me to drop the good submirror
and recreate the mirror and attach each submirror again.  I was also
concerned over the vagueness of the examples as to which submirror would
overwrite the other.  The last thing that I wanted to have happen is for
the good submirror to be overwritten by the blank disk.

I've seen  this done by Keystone Sysadmins that I've worked with in the past
along with having raid errors pop up all over the place an entire mirrors
drop due to the fact that the cables were plugged in and not thumbscrewed in
or not tightened and then the cables come loose or fall off their connectors
on the backs of arrays.

The same ones that blamed me for destroying their main image when they had a
2u rack server laying on its side on the floor, not flat like it would make
sense but on the side and proclaimed that when I bumped the cubicle wall
with a cart that I had some printers on I knocked it over, and the drive
died and that they lost all of their work and that I should be more careful
next time.  I asked why they didn't have backups, why they had it sitting in
such a stupid position and more importantly how this could happen when due
to the position of the power supply only the cord and not the sevrver could
be touching the wall and well what about the air flow?  I got no response to
that one.

One of them told my boss "We are running raid 5 we will never have to do
backups again." because he didn't like to do backups.  I almost fell down in
laughter.

One of them setup the pool of web severs and because he was playing around
with DHCP decided that would be the way to assign addresses to it because it
was 'cool' I pointed out that this was ridiculous and if the server was down
that all of the machines would loose their addresses.  90 days go by and in
these 3 months one of the squirrelly KS's that always has to mess with
things reformats the dhcp server to do something else.  All of the servers
begin to drop offline like flies sequentially in the order they were powered
on three months ago.

The same KS also had the system monitoring running on a machine that was
running a release candidate of windows 2000.  A RC that had a bug where
theTCP/IP stack would randomly freeze up for an undetermined amount of
time.  This meant that there would be periods of no monitoring and also when
it would unfreeze it would send out 80 pages saying that each server was
down.  When I installed WhatsUp on one of the macintoshes they told my boss
that I was crashing the servers by pinging them once a minute and that I was
generating an overload of network traffic and that I needed to turn it off.

Ah well, thanks again everyone for their input.  I too prefer to 'break'
things and 'prove' that replacement failover / raid reattachments do in fact
work and do so properly.  You end up with a better understanding of how a
repair is supposed to go and the timeframe for it to take place.  I
unfortunately have walked into a situation where there are many legacy
systems to consider the dependancies are ridiculous at times and the
documentation is non-existant.

Thanks,

Brian
On 9/6/07, Sandwich Maker <adh at an.bradford.ma.us> wrote:
>
> " From: "Ahmed Ewing" <aewing at gmail.com>
> "
> " []
> "
> " This is akin to Phil's suggestion, except that the number of replicas
> " on the root disks would float so that together they are never
> " outnumbered by the collective external storage. 3 apiece for each
> " 6-slot Multipack, 6 apiece for each 12-slot D1000, etc. Even the new
> " larger size of 4mb each replica is still negligible on today's
> " cavernous disks.
>
> you don't have to accept the default 4M size; you can specify how
> large you want it.  when i set it up on my system, i allocated a 1-cyl
> slice on each disk and jiggered the math so that 3 dbs would fit.
>
> i agree though; when you're talking about 100s of Gb per disk, 4M is
> negligible.
> ________________________________________________________________________
> Andrew Hay                                  the genius nature
> internet rambler                            is to see what all have seen
> adh at an.bradford.ma.us                       and think what none thought
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