<div dir="ltr">Simon,<br><br>Pay attention that /boot can be installed only on a single disk or RAID-1 where every disk can actually work as a stand alone disk.<br><br>I personally decided to use RAID-5 on 3 disks with RAID-1 on 3xsmall partitions for /boot and RAID-5 on the rest.<br>
RAID-5 also allows easier expansion in the future.<br><br><br><div class="gmail_quote">On Tue, Nov 10, 2009 at 8:48 PM, Simon Baxter <span dir="ltr"><<a href="mailto:linuxtv@nzbaxters.com">linuxtv@nzbaxters.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Thanks - very useful!<br>
<br>
So what I'll probably do is as follows...<br>
* My system has 4x SATA ports on the motherboard, to which I'll connect my 4x 1.5TB drives.<br>
* Currently 1 drive is in use with ~30G for / /boot and swap and ~1.4TB for /media<br>
* I'll create /dev/md2, using mdadm, in RAID1 across 2 ~1.4TB partitions on 2 drives<br>
* move all active recordings (~400G) to /dev/md2<br>
* split /dev/md2 and create a raid 1+0 (/dev/md1) using 4x partitions of ~1.4TB across 4 drives<br>
<br>
At this point I have preserved all my data, and created a raid1+0 for recordings and media.<br>
<br>
I should now use the remaining ~100G on each drive for raid protection for (root) / and /boot. I've read lots on the web on this, but what's your recommendation? RAID1 mirror across 2 of the disks for / (/dev/md0) and install grub (/boot) on both so either will boot?<div>
<div></div><div class="h5"><br>
<br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
On Tue, Nov 10, 2009 at 09:46:52PM +1300, Simon Baxter wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
What about a simple raid 1 mirror set?<br>
<br>
</blockquote>
<br>
Ok.. short comparison, using a single disk as baseline.<br>
<br>
using 2 disks<br>
raid0: (striping)<br>
++ double read throughput,<br>
++ double write throughput,<br>
-- half the reliability (read: only use with good backup!)<br>
<br>
raid1: (mirroring)<br>
++ double read throughput.<br>
o same write throughput<br>
++ double the reliability<br>
<br>
<br>
using 3 disks:<br>
<br>
raid0: striping<br>
+++ tripple read performance<br>
+++ tripple write performance<br>
--- third of reliability<br>
<br>
raid1: mirroring<br>
+++ tripple read performance<br>
o same write throughput<br>
+++ tripple reliability<br>
<br>
raid5: (distributed parity)<br>
+++ tripple read performance<br>
- lower write performance (not due to the second write but due<br>
to the necessary reads)<br>
+ sustains failure of any one drive in the set<br>
<br>
using 4 disks:<br>
<br>
raid1+0:<br>
++++ four times the read performance<br>
++ double write performance<br>
++ double reliability<br>
<br>
<br>
please note: these are approximations and depending on your hardware<br>
they may be off by quite a bit.<br>
<br>
cheers<br>
-henrik<br>
<br>
<br>
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</blockquote>
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