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<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy">Actually good RAID controllers store the RAID set information on the controller AND the disks in the RAID set. If there is a mismatch
the controller’s BIOS will tell you and let you decide which is correct. I’ve done this more than once here. Usually it occurs when the battery on the RAID controller fails but in a recent incident we lost a disk but for some reason the hardware didn’t
detect it as a lost disk – just that it couldn’t read RAID SET info from it (it displayed a nice green light but the controller BIOS indicated it was a 0 MB disk which is how I knew it was bad – first time I’ve ever seen this happen). It is such mismatches
that are the scariest issue because if you just blindly answer you can end up blowing away the RAID set. We haven’t done that on a Linux box yet but I gather our Windows Admins did it at least once. Note that it isn’t something that occurs frequently
but with more than 100 servers over a 7 year period though you’re going to see it.<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy">Years ago I worked for a company that had about 300 customer sites. About once every couple of weeks we’d have a site go down for one
reason or another and it was always seen as a big deal. We later signed a customer with over 2000 sites so saw site failures about twice a week. The President of the company saw me in the elevator and expressed concern about the high rate of failures.
I pointed out that the rate hadn’t really increased – just the volume because the number of sites had grown greatly so even at same rate. Sometimes basic math skills give you the reason with no need for further analysis. (That reminds me of the Dilbert
strip where someone points out the PHB that 40% of absences occur on Mondays and Fridays and the PHB decides he needs to get to the root of the issue while Dilbert is saying “You’re joking right?”)<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy"><o:p> </o:p></span></font></p>
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<p class="MsoNormal"><b><font size="2" face="Tahoma"><span style="font-size:10.0pt;
font-family:Tahoma;font-weight:bold">From:</span></font></b><font size="2" face="Tahoma"><span style="font-size:10.0pt;font-family:Tahoma"> ale-bounces@ale.org [mailto:ale-bounces@ale.org]
<b><span style="font-weight:
bold">On Behalf Of </span></b>Jim Kinney<br>
<b><span style="font-weight:bold">Sent:</span></b> Sunday, February 12, 2012 11:59 PM<br>
<b><span style="font-weight:bold">To:</span></b> transam@verysecurelinux.com; Atlanta Linux Enthusiasts<br>
<b><span style="font-weight:bold">Subject:</span></b> Re: [ale] raid suggestions</span></font><o:p></o:p></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:
12.0pt"><o:p> </o:p></span></font></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><br>
Add to it that pretty much ALL hardware RAID is closed proprietary stuff. I can't trust what I can't open and evaluate. And I sure don't like having my feet to the fire for something I really can't fix.<br>
<br>
<o:p></o:p></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:
12.0pt">On Sun, Feb 12, 2012 at 11:22 PM, Bob Toxen <<a href="mailto:transam@verysecurelinux.com">transam@verysecurelinux.com</a>> wrote:<o:p></o:p></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:
12.0pt">On Thu, Feb 09, 2012 at 08:37:03PM +0000, Lightner, Jeff wrote:<br>
> Hardware based (for true RAID) because it doesn't require CPU cycles.<o:p></o:p></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:
12.0pt">Some hardware RAID controllers store critical information on the<br>
controller. Thus, a fried controller means all data lost!<br>
<br>
This happened about 2 years ago to one of the smartest Linux guys I<br>
know!<br>
<br>
Thus, I'll only consider software RAID if it's up to me!<br>
<font color="#888888"><span style="color:#888888"><br>
<span class="hoenzb">Bob</span></span></font><o:p></o:p></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:
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<br>
> -----Original Message-----<br>
> From: <a href="mailto:ale-bounces@ale.org">ale-bounces@ale.org</a> [mailto:<a href="mailto:ale-bounces@ale.org">ale-bounces@ale.org</a>] On Behalf Of Calvin Harrigan<br>
> Sent: Thursday, February 09, 2012 3:26 PM<br>
> To: Atlanta Linux Enthusiasts<br>
> Subject: Re: [ale] raid suggestions<br>
><br>
> As per a discussion on the list a few months ago, software based raid 10.<br>
><br>
> On 2/9/2012 2:54 PM, Geoffrey Myers wrote:<br>
> > I've not played with raid stuff of late. What is the recommended<br>
> > configuration for a small business these days? Definitely want data<br>
> > protection, but don't want to sacrifice a lot of speed for that purpose.<br>
> ><br>
> > Thoughts?<br>
> ><br>
><br>
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><br>
><br>
><br>
><br>
> Athena(r), Created for the Cause(tm)<br>
> Making a Difference in the Fight Against Breast Cancer<br>
><br>
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_______________________________________________<br>
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See JOBS, ANNOUNCE and SCHOOLS lists at<br>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><br>
<br clear="all">
<br>
-- <br>
-- <br>
James P. Kinney III<br>
<br>
As long as the general population is passive, apathetic, diverted to consumerism or hatred of the vulnerable, then the powerful can do as they please, and those who survive will be left to contemplate the outcome.<br>
- <i><span style="font-style:italic">2011 Noam Chomsky<br>
<br>
<a href="http://heretothereideas.blogspot.com/" target="_blank">http://heretothereideas.blogspot.com/</a></span></i><o:p></o:p></span></font></p>
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