Re: install Etch with raid level 10
On Thu, 27 Sep 2007, Goswin von Brederlow wrote:
True but not the only reason. Random access time for read goes down
for raid1 and if you don't have a bottleneck raid1 will not be
noticeably slower than a signle disk on write. As swapin is totaly
random normaly that would be probably twice as fast on raid1 compared
to one disk.
yes, but I suppose you get this latter benefit as well just using two swap
partitions at the same priority, since the kernel will try and do striping
anyway. Indeed, swapouts should be faster using 2 swap partitions without
raid1, since in this case the kernel ought to write pages to the two disks
at once. So, summing up:
- swap on raid1 swaps out at the speed of the slowest disk, swaps in at the
sum of the speeds of the two disks, but the system will stay up and running
even in the case of failure of one of them;
- swap on 2 disks (no raid1) swaps both out and in at the sum of the speed
of the disks, but failure of any one of the disks brings down your
system in flames, possibly trashing cached data in the process.
Correct?
Bye
Giacomo
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