>>>
>>>I'm sorry if I'm not agree with you. AFAIK RAID 5 with 3HD is, 1 as primary, 1 as mirror and the other one as ECC. You cannot spread/stripe harddisk without the use of RAID 5+0. But I never did like you said. Can we stripe the HD with RAID 5 ?
>>
>>The server at a previous job has 3 hard disks of 4.5 GB each, and the total capacity is 9 GB. If what you said is true, only 1 of the 3 hard disks would be used.
>>
>>The server supposedly has RAID 5, but I didn't previously investigate the differences between RAID 5 and RAID 5+0.
>>
>>The definition at
http://www.pcwebopedia.com/TERM/R/RAID.html says:
>>
>>"...Level 5: Provides data striping at the byte level and also stripe error correction information. This results in excellent performance and good fault tolerance."
>>
>>The definition also includes several links; see the definition of RAID 5 at
http://www.acnc.com/04_01_05.html.
>>
>>I see no mention of 5+0 at the mentioned sites.
>
>Well.. I never aware that RAID 5 is stripe at the byte level. But I seriously doubt it can spread evenly between HD (like RAID 0) because this is where you gain a true performance. No redundancy, no fault tolerant, no mirroring, just performance. And that's also why we cannot called RAID 0 as a "real" RAID
If you look at the graphic, at the link I gave (
http://www.acnc.com/04_01_05.html), it seems that in the example (5 hard disks), for the first 4 bits (?), the data is spread evenly among 4 disks, whereas the 5th. hard disk provides redundancy.
Later, for other data blocks, the disks are changed (that is, another disk takes over the "redundancy" role).
In the example, one would suppose that data can be read 4 times as fast as when you don't use RAID -
and you have redundancy.
> ...The controller will do it's job, it will switch automatically if one of the disk is damage. But if you don't replace it with another one than you won't get a good fault tolerance. But I maybe wrong about this.
Yes, that is my understanding, too. If one of the disks gets damaged, it has to be replaced ASAP.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
