I know this sounds crazy but would you be able to use raid 0 to make transfer speeds much faster  or even raid 5 if you wanted more security for your parity drive?

There is at least one person with RAID0 parity. RAID5 makes no sense because the parity drive is no more important than any other drive and possibly less because it contains no user data.

How much faster speeds would you get with raid 0 parity. Is that where the bottleneck is? writing to the parity drive? Because I am watching my processor and it doesn't go above 30 percent and I have 4 gigs of ram and it only uses 2ish

How much faster speeds would you get with raid 0 parity. Is that where the bottleneck is? writing to the parity drive? Because I am watching my processor and it doesn't go above 30 percent and I have 4 gigs of ram and it only uses 2ish

The bottleneck is the rotational speed of the slower of the two drives involved (the parity drive and the data drive)  Any given sector must FIRST be read from both involved disks and then the respective disks rotate at least one revolution so the disk heads are again over the same sector so they can then write the sector that was just read.

 

This has been asked, described, and discussed many times.  A search in the wiki should result in lots more detail.

 

Joe L.

It's not that much faster, about 3MB/s depending on controller and drive models.

However, if you are using multiple drives with allot of random I/O's (think bittorrent) it does help allot.

 

I use the Areca controller which also does caching so I get some good throughput with minimal latency.

It all depends on how much data and what your usage patterns are.

For basic media storage the extra expenditure may not be worth it.

For me, unRAID is my main file server for allot of applications, so it was worth it for me.

I scored an ARC-1200 on eBay for around $99.

I used 2 Seagate 1.5TB 7200 RPM 32MB cache in a raid set of

2TB Raid 0 and 350GB RAID 1 for cache.  So I have a RAID0 parity and a RAID1 Cache.

I rarely use the cache drive to cache data to the unRAID array.

Instead I use the cache drive's raid1 config for local storage of apps and data that I want protected in a different manner.

I.E. my imap historical mail store, /homes store and other applications.

(Of which I rsync on a daily basis to a protected spindle drive on the unRAID array).

It's not that much faster, about 3MB/s depending on controller and drive models.

However, if you are using multiple drives with allot of random I/O's (think bittorrent) it does help allot.

It is most helpful if you are WRITING multiple data drives with allot of random I/O's.  it would have no impact on reads.

It's not that much faster, about 3MB/s depending on controller and drive models.

However, if you are using multiple drives with allot of random I/O's (think bittorrent) it does help allot.

It is most helpful if you are WRITING multiple data drives with allot of random I/O's.   it would have no impact on reads.

 

It helps with writes to a single drive too.

It's a measurable increase in speed, albeit a small one compared to the cost.

On the upside, you can split the two drives into RAID0(pairty)/RAID1(cache).

The Areca controller will sound an audible alarm if a drive fails.

 

Also you can use something like the Silicon Image Steelvine processors to get the RAID0 across multiple drives.

http://www.addonics.com/products/host_controller/ad2sahpmeu.asp

 

They also have a SAFE mode where two drives can be split between RAID0/RAID1 subsystems.

The Steelvine Port multiplier uses a single SATA port to fan out to 2 drives so you are limited in speed.

I measured this one at an additional 3MB/s also.

You loose the caching and alarm facility that the Areca ARC-1200 bring.

 

FWIW,

The steelvine PMP does not spin down unused drives.

The ARC-1200 can spin down unused drives after a programmable period of inactivity.