[mythtv-users] OT Hardware RAID 5 Recommendations
beww at beww.org
Tue Dec 12 19:26:15 UTC 2006
On Dec 12, 2006, at 12:15 PM, Yan Seiner wrote:
> George Galt wrote:
>> Thanks, I'm looking for RAID5 which requires that a parity bit be set
>> across all of the disks. This requires a fair bit of horsepower.
>> RAID1 is (if I remember correctly) simply a mirror, which would be a
>> waste of disk space. On that point, I'm not sure if software RAID
>> does level 5.
> I've been doing software RAID5 for years.
> There's nothing to it; it barely loads up the CPU, even on
> If you need to sync a new drive, that will take a while, but otherwise
> in operation it is transparent.
Hmmm... I haven't seen actual numbers but calculating the parity info
does require *some* CPU. The last time I compared them, systems
with H/W RAID5 were significantly faster than ones using S/W RAID,
but that was back when a 400Mhz. CPU was "fast".
One big advantage to software RAID is that the drives can be used on
any Linux system without needing specific hardware, where hardware
RAID depends on a specific card type being available. If a card type
is discontinued you could potentially be in trouble, while with a S/W
RAID system you should always be able to get your info in the event
of H/W failure.
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