[mythtv-users] Contemplating a major change

Stephen P. Villano stephen.p.villano at gmail.com
Sun Apr 6 18:46:50 UTC 2014


On 4/6/14, 2:24 PM, Gary Buhrmaster wrote:
> On Sun, Apr 6, 2014 at 6:05 PM, Stephen P. Villano
> <stephen.p.villano at gmail.com> wrote:
>> On 4/6/14, 12:49 PM, Raymond Wagner wrote:
> ....
>>> The "hardware" part was key.  The only thing hardware RAID10 gives you
>>> over software is ease of boot.  Hardware RAID is only beneficial when
>>> you have to perform parity calculations, and even then it's largely
>>> inconsequential on a modern CPU.
>>> _______________________________________________
>> For RAID10, perhaps, perhaps not. It's used in enterprise for a good reason.
> And many of those enterprise controllers also have various
> battery backed caches.  Which *can* have benefit for
> certain workloads (often databases), although various
> SSD devices are now the usual accelerator since the
> logs tend to be small enough (even a ZIL on a large
> ZFS installation can often fit in a reasonably priced
> (for enterprise quality) SSDs), and the L2ARC is also
> moving to SSDs for more performant target installations.
I don't know. Logs are *usually* small, but when something goes wrong,
well, my Mythbuntu 12.04 ended with five gigs of errors and climbing
once, with a backup of 5 gigs of compressed log.
Logs are typically small until a system error occurs, then the sky's the
limit!
Don't know what the error was, it seemed to impact multiple processes,
so it probably was something in the kernel flipped sideways. A reboot
cleared it up. About the only environmental thing I can think of is we
were having a mild geomagnetic storm at the time and one other system
started to act flakey, necessitating a reboot, so perhaps a surge of
some sort made it past the filters.
Or it was digital gremlins.  ;)
>> That said, one' speaking of higher end hardware in the RAID controller
>> than the usual card a consumer would acquire.
> ....
>> That said, I've not found many inexpensive RAID cards out there
>> (inexpensive as under $300) for current drives.
> Pretty much the only thing one can find (in the sub-$300 category)
> is enterprise RAID cards that are in the "new to you" market space
> after having been removed from an enterprise server.  And you
> usually have to plan to replace the battery, further reducing your
> target price.
>
> I suspect Raymond was responding to HW RAID10 cards
> that consumers tend to purchase (or implement in their
> BIOS via something like the ICHxR chipsets), and for
> that, he is right.
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