Author Topic: Raid 0 (Read 338 times)

Octavius · « **on:** May 04, 2005, 06:08:37 PM »

I think I finally put together my first RAID combo (two Seagate 7200.7 80gb).

One small question: Should the total drive space display ~80, or ~160?

I'm showing the latter. That said, since they are stripped, would ~50mb of data "appear" as ~100mb used?

Blammo · « **Reply #1 on:** May 04, 2005, 06:28:48 PM »

Hey Octavius:

Same sort of set up I have and yes, a Raid striped 0 with two 80 GB HDDs should show around 160 (for me it is about 153.5 GB or so).

Oh, and ~ 50 MB used is only ~ 50 MB used. It simply divides the file across the two drives so each drive would be hold ~ 25 MB of the total ~ 50 MB.

Overlag · « **Reply #2 on:** May 04, 2005, 08:28:52 PM »

its mirrors that half your space (raid1)
stripping still leaves you all the space (raid0)

Octavius · « **Reply #3 on:** May 05, 2005, 02:42:54 PM »

Cool, thanks

TequilaChaser · « **Reply #4 on:** May 06, 2005, 12:57:36 PM »

but if you have a hard drive failure with RAID 0 , you are basically screwed! only will have 1/2 of everything left!

that was my take when reading up on it. And if you have a fast machine and even better are using SATA HDs you will not notice a performance hit if you go RAID 1 ( mirrored )

Vipermann · « **Reply #5 on:** May 06, 2005, 01:03:45 PM »

That's not true, you won't have half of anything.

RAID 0 writes bits to both disks in such a way that if you lose one disk you lose everything that was on both.

You are correct that RAID 1 will rarely show a performance hit on a decent computer. In addition you may see a small gain in read performance in a RAID 1, but nothing like with RAID 0.

Skuzzy · « **Reply #6 on:** May 06, 2005, 01:20:23 PM »

RAID levels and a brief explanation of each:

RAID 0 -- Striped disk array without fault tolerance: Provides data striping (spreading out blocks of each file across multiple disk drives) but no redundancy. This improves performance but does not deliver fault tolerance. If one drive fails then all data in the array is lost.

RAID 1 -- Mirroring and duplexing: Provides disk mirroring. RAID 1 provides, up to, twice the read transaction rate of single disks and the same write transaction rate as single disks.

RAID 2 -- Error-Correcting Coding: Not a typical implementation and rarely used, RAID 2 stripes data at the bit level rather than the block level.

RAID 3 -- Bit-interleaved parity: Provides byte-level striping with a dedicated parity disk. RAID 3, which cannot service simultaneous multiple requests, also is rarely used.

RAID 4 -- Dedicated parity drive: A commonly used implementation of RAID, RAID 4 provides block-level striping (like RAID 0) with a parity disk. If a data disk fails, the parity data is used to create a replacement disk. A disadvantage to RAID 4 is that the parity disk can create write bottlenecks.

RAID 5 -- Block interleaved distributed parity: Provides data striping at the byte level and also stripe error correction information. This results in excellent read performance, good fault tolerance, but slower writes. RAID 5 is one of the most popular implementations of RAID.

RAID 6 -- Independent data disks with double parity: Provides block-level striping with parity data distributed across all disks.

RAID 0+1 -– A Mirror of Stripes: Not one of the original RAID levels, two RAID 0 stripes are created, and a RAID 1 mirror is created over them. Used for both replicating and sharing data among disks.

RAID 7 -- A trademark of Storage Computer Corporation that adds caching to RAID 3 or 4

RAID 10 -– A stripe of mirrors: Not one of the original RAID levels, multiple RAID 1 mirrors are created, and a RAID 0 stripe is created over these.

Grits · « **Reply #7 on:** May 06, 2005, 10:09:41 PM »

In a CPU critical game like AH is it a bad idea to use software RAID, and if so, whats the best hardware RAID controller card for a simple 2 disk SATA RAID setup? 3Ware seems to have a decent priced true hareware RAID controller card in the 8000 series.

Vipermann · « **Reply #8 on:** May 06, 2005, 10:40:32 PM »

IMO software RAID is almost always a bad idea. There may be some instances where it can save data but in most cases it won't help you.

3ware makes some good controllers. I've used them in several mid-range server setups with SATA drives and they have performed very well. Most also support hot swapping and hot spares which is excellent for server setups.