SSD RAID help.

[koal7]

Hey everybody I was hoping you all could help me get my head around different raid setups a little bit, I have been searching so please don't just say Google it.

Raid 0 vs RAID 1: I get how they work. RAID 0 splits the data between two drives, Raid 1 duplicates.

Here is my problem.

Everything I read says RAID 0 is best performance because it can access the data faster.

Why is having half the data on one drive, and half on another, better than having all of the data on both drives?

All of the data on the RAID 0 setup is also on the RAID 1 setup. All of the data could be accessed just as quickly. PLUS if two bits of information were needed and both were on the same hard drive in RAID 0, wouldn't that mean in RAID 1 they could be read simultaneously?

This is a theoretical budget be damned question about which system actually retrieves data at a faster rate.

If anybody could help me out with this I would greatly appreciate it.

 

[Josh Weston]

You do get a read performance increase from RAID1, as, like you said, the data can be read from each drive independantly. However, as far as I understand, it's not as efficient as RAID0 for this, just because it's meant for redundancy over speed.
RAID0 comes into its own for write performance, as only half of the data is actually being written to each drive.

As for if the two bits of data were found on one single RAID0 drive, this negating the 'stripe' effect, I don't think that can happen. The stripe size is too small for two pieces of coherent data to have got onto one of the drives. This is why if one drive fails, every last bit of data on both of the drives is lost.

I hope this has helped you, although it's 4am here so I bet I could have explained it a little better

 

[koal7]

You do get a read performance increase from RAID1, as, like you said, the data can be read from each drive independantly. However, as far as I understand, it's not as efficient as RAID0 for this, just because it's meant for redundancy over speed.
RAID0 comes into its own for write performance, as only half of the data is actually being written to each drive.

As for if the two bits of data were found on one single RAID0 drive, this negating the 'stripe' effect, I don't think that can happen. The stripe size is too small for two pieces of coherent data to have got onto one of the drives. This is why if one drive fails, every last bit of data on both of the drives is lost.

I hope this has helped you, although it's 4am here so I bet I could have explained it a little better

Thank you very much, this has cleared up my confusion completely.

 

[Josh Weston]

Glad to have helped