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replies embedded (pun intended):<br>
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<div class="moz-cite-prefix">On 06/12/15 07:53, Kirk D Mccann wrote:<br>
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<div dir="ltr">So I've noticed two things that no one has
mentioned yet. 3 drives running in raid 0 and rebuild times of
large drives.
<div><br>
</div>
<div>Raid 0:</div>
<div>You realize that if any one of the drives that are running
in raid 0 fail then you lose all your data right? The only
time you want to use raid 0 is when you dont care about the
data and are looking for speed. I use raid 0 for our build
server build drive because we always have source code that can
be used to rebuild the builds.</div>
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</div>
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The two sets of RAIDs are on different machines right now. The
striped 0's are used for video capture, then they are compressed and
put on different media (blu-ray write-once usually), and then that
video is deleted from the stripe array.<br>
<br>
<br>
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<div dir="ltr">
<div>Large Drives:</div>
<div>So if you have more two drives mirroring isnt really what
you want because true mirroring only works with two sets.
(That could be two drives or two sets of raided disks).</div>
<div>Since you have more than two drives you are going to want
raid 5,6, or 7. The raid that you choose should be based on
the size of your drives and the class of the drives.</div>
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<br>
The mirrored drives, qty 2, are each 2 Tb, and are identical
drives. Again, intent is easy failover without losing existing
data. I'm horrible about doing the proper backups at home. (Like
the mechanic's personal car always needs a lot of work.)<br>
That machine is not a data or compute intensive one. Email, games,
and such.<br>
<br>
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<div dir="ltr">
<div><br>
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<div>If the drives you have are more than 1TB in size and they
are consumer grade drives then you shouldn't be using raid 5.
<br>
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I was incorrect; they are RAID 1.<br>
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<div dir="ltr">
<div>This is a problem because the likelihood of a read failure
while rebuilding a disk is higher the larger the drives are.
So then you have to be able to handle a read failure which
requires a higher raid. Check out the calculator: <a
moz-do-not-send="true"
href="http://www.servethehome.com/raid-calculator/raid-reliability-calculator-simple-mttdl-model/">http://www.servethehome.com/raid-calculator/raid-reliability-calculator-simple-mttdl-model/</a></div>
<div><br>
</div>
<div>Also if you are using raid dont use Western Digital Green
drives unless you plan to reflash the firmware to make them
function like red drives.</div>
<div><br>
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Will look further into ZFS. <br>
<br>
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<div dir="ltr">
<div>My recommendation:</div>
<div>All that being said I am a big fan of Freenas, because it
uses ZFS. Btrfs is great but its not quite where ZFS is
yet(or at least that was the case when I last looked at it).
If you go the ZFS route you REALLY REALLY need to read up on
how ZFS, uDevs, and vDevs work. Because what many people dont
realize is you cant just add a single disk to the array when
you do it makes the entire array fail if that single added
disk fails. When you add drives you have to add drives in
sets.</div>
<div><br>
</div>
<div>Personally I'm paranoid about my data, I use ZFS raid z3 on
two vDevs, each vDev has 5 2+TB drives. </div>
<div><br>
</div>
<div>Oh and with ZFS you can use different size drives but you
waist a good amount of space when you do that. </div>
<div>And lastly be sure to schedule scrubs of your drives and do
it in a way that the scrub will not occur while a long smart
test is running. That can cause problems.</div>
<div><br>
</div>
<div>-Kirk</div>
</div>
<div class="gmail_extra"><br>
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Thanks!<br>
<br>
<br>
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<div class="gmail_extra">
<div class="gmail_quote">On Thu, Jun 11, 2015 at 5:33 PM,
WebDawg <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:webdawg@gmail.com" target="_blank">webdawg@gmail.com</a>></span>
wrote:<br>
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<div dir="ltr">
<div>
<div class="h5"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, Jun 11, 2015 at
3:30 PM, WebDawg <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:webdawg@gmail.com"
target="_blank">webdawg@gmail.com</a>></span>
wrote:<br>
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0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div dir="ltr"><span>On Thu, Jun 11, 2015 at
3:11 PM, david <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:ainut@knology.net"
target="_blank">ainut@knology.net</a>></span>
wrote:<br>
</span>
<div class="gmail_extra">
<div class="gmail_quote"><span>
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style="margin:0 0 0
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I'm thinking about putting all the
computers on the network disk array,
including the SOC's: beaglebone
blacks, arduino mega256, and the
RPi2. I would not mind doing the
compiles (and maybe even the
booting!) on the hard drives instead
of the limited-life SD cards and
'flash' that are on the SOC's. Any
of you guys done that? Everything
in the house is 1Gb Ethernet. If
only I could get that to the outside
world <heavy sigh.> <span><span>
:-) </span></span><br>
Already have the BBB's booting of
the SD card, which you have to do
with the rev B's and their 2 Gb
size..<span><font color="#888888"><br>
<br>
David</font></span>
<div>
<div><br>
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<div><br>
</div>
</span>
<div>I have thought about it. At that
point you need to consider the transport
mechanism between the systems and such.
NFS, CIFS, iSCSI?<br>
<br>
</div>
<div>You need to back up. Live. (ZFS
Snapshot)<br>
<br>
</div>
<div>I do not know what you do with them,
so I cannot help there.<br>
<br>
</div>
<div>PXE boot? Other ways to boot? I do
not know a lot about that stuff except
the RPi.<br>
<br>
</div>
<div>I would consider bonding more then
one port together on the network server
if you are doing anything major.<br>
<br>
</div>
<div>I run some VMS over NFS right now, I
do not like it.<br>
<br>
</div>
<div>I was using CIFS but after learning
that is really bad to do over and over
again. I stopped. None of this was
mission critical.<br>
<br>
</div>
<div>I want speed so I am leaning towards
some physical disks for the virtual
systems. In the future I would use a
fiber target or bonded target that was
dedicated if I wanted network stuff.<br>
<br>
</div>
<div>Fun Fun.<br>
</div>
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<div class="gmail_extra">I forgot to mention. You are
going to need a few UPS units. I have destroyed virtual
systems when a server that hosts its filesystem has went
down. It is not fun bringing it back to life.<br>
<br>
</div>
<div class="gmail_extra">If you are talking about creating
and image, and having the devices pull any new images
when new ones exist, still using them on the SD cards
while they are on, I think you have a different
situation all together.<br>
</div>
</div>
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