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Jim Cheetham wrote:
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cite="mid:f4cc59760906150238x3b14c617h9645d24daba563b2@mail.gmail.com"
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<pre wrap="">On Mon, Jun 15, 2009 at 8:16 PM, Karl Leaning<a class="moz-txt-link-rfc2396E" href="mailto:mythtv@objectivity.co.nz"><mythtv@objectivity.co.nz></a> wrote:
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<pre wrap="">Umm, no with raid 5, you lose a drive not the data. add a new drive
"rebuild" the set and continue as normal...
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<pre wrap=""><!---->
Yes, true. Do you have a spare drive online? If you did, wouldn't you
be using it as a hot spare or part of the data set already?
If you lose a second drive while one drive is out of action ... you
lose data. Gone.
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Almost everything which has been mentioned in this thread is correct.
It just comes down to what experiences you have had in the past.<br>
<br>
I have to agree that RAID is not a backup solution. I run 2x 1TB USB
disks for off-site backup (no tv episodes or DVD rips make it onto
these as they are all disposable).<br>
<br>
For data continuity on the other hand, I run the disks on my SAN in a
RAID-5 set.<br>
<br>
Recently one of the 1TB disks threw 'recoverable'[1] errors up in the
kernel log.<br>
<br>
I called my equipment supplier and lodged an RMA. Took 2 days.<br>
When they had my new drive ready, I pulled the faulty drive out of the
hotswap bay[2][3] and swapped it with them.<br>
I put the new drive in, it rebuilt, nothing missed a beat.<br>
<br>
Now sure there are a number of things which could have gone wrong
during this process. Most of them have been covered (second disk
failing while I had the first one out, rebuild failing, disk TOTALLY
failing while waiting for the RMA). It is important to note however
that in his case it all went as planned.<br>
<br>
So while people are correct to talk about potential disaster from
running RAID-5. These are not guaranteed outcomes, sometimes it
doesn't effect WAF at all. =)<br>
<br>
<br>
<br>
Dean<br>
<br>
[1] these errors are never recoverable. As mentioned earlier, ANY
errors are bad, replace the disk immediately.<br>
[2] $25 was what they cost. Worth their weight in gold.<br>
[3] Always label the front of the caddy with the serial number of the
disk inside. You can then know which drive to pull. Otherwise if you
pull the wrong one, you may be in trouble.<br>
<br>
<br>
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