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Old 02-27-2006, 05:32 AM   #1
spoody_goon
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onboard serial ata = raid?


Easy question, is a sata just a raid that is software raid instead of hardware? If so I assume by turning on the sata funciton in my bios will cause my 2 hard drives to be read as one.
Does sata have the same benifits (speed) as hardare raids?
Could I expect faster speeds that by using 2 seperate hard drives?

Thanks

[Edit]
It looks like I am after a raid-0 for the striping, but I have 2 different sizes in my hard drives 1 40 gig and 1 120 gig. Does that create a big problems?
[/Edit]

Last edited by spoody_goon; 02-27-2006 at 05:42 AM.
 
Old 02-27-2006, 05:44 AM   #2
asimba
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Nopes - Serial ATA is just a interface like a IDE/Parallel ATA or PATA.
I dont really seem to understand what makes you equate SATA=RAID.

As far as speed goes - SATA Hard drives are usually faster then IDE/PATA since they its overclocked. And its unfair to compare yesteryears IDE's with Newer SATA - since many things have changed like spin rate buffering etc.

If you compare RAID and SATA Hard drives. I beleive a Hardware SCSI RAID 0 can beat Newer SATA Hard drives anytime.
 
Old 02-27-2006, 05:46 AM   #3
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Depends on the type of chipset in the controller as to whether its true hardware raid or fakeraid (software) a bit like the way winmodems work.

As for speed it can vary depending on the type of RAID configuration you choose 0, 0+1, 1 ,5 etc. But the overall speed will be dependent on the speed of the fastest drive.

http://data-recovery.lsoft.net/concept_raid.html

Note: Sata is not a RAID technology its a driver controller technology, you can have SATA without any kind of RAID.
 
Old 02-27-2006, 05:51 AM   #4
spoody_goon
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Quote:
Originally Posted by asimba
I dont really seem to understand what makes you equate SATA=RAID.
Lack of knowledge that's why I appriciate your help.
 
Old 02-27-2006, 06:03 AM   #5
spoody_goon
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Last question,
If I am looking for raid-0 hardware via pci, is there a big difference between the cheep raid cards ($69) and the expensive raids ($269)

Quote:
Originally Posted by okmyx recomended reading
The total size of this RAID is the size of the smallest hard disk drive multiplied by the number of the hard disk drives.
Having 2 different sizes of hard drives 1-40 gig and 1-120 gig it sound like a raid is not for me. Do you agree?

Thanks
 
Old 02-27-2006, 06:12 AM   #6
asimba
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Excerpt from Scott Mueller (Upgrading PC's) :

The performance of SATA is impressive, although current hard drive designs can't fully take advantage of its bandwidth. Three variations of the standard are proposed that all use the same cables and connectors; they differ only in transfer rate performance. Three SATA's SATA-150/SATA-300/SATA-600

Serial ATA uses a special encoding scheme called 8B/10B to encode and decode data sent along the cable. The 8B/10B transmission code originally was developed (and patented) by IBM in the early 1980s for use in high-speed data communications

And sure you can find more information at http://www.serialata.org.

---------------------------------------------------------------

Excerpt from Scott Mueller (Upgrading PC's) :

Where is RAID is just a array of discs - RAID is just its expanded form. And with RAID

RAID is an acronym for redundant array of independent (or inexpensive) disks and was designed to improve the fault tolerance and performance of computer storage systems. RAID was first developed at the University of California at Berkeley in 1987, and was designed so that a group of smaller, less expensive drives could be interconnected with special hardware and software to make them appear as a single larger drive to the system. By using multiple drives to act as one drive, increases in fault tolerance and performance could be realized.

Initially, RAID was conceived to simply enable all the individual drives in the array to work together as a single, larger drive with the combined storage space of all the individual drives added up. However, this actually reduced reliability and didn't do much for performance, either. For example, if you had four drives connected in an array acting as one drive, you would be four times as likely to experience a drive failure than if you used just a single larger drive. To improve the reliability and performance, the Berkeley scientists proposed six levels (corresponding to different methods) of RAID. These levels provide varying emphasis on either fault tolerance (reliability), storage capacity, performance, or a combination of the three.

An organization called the RAID Advisory Board (RAB) was formed in July 1992 to standardize, classify, and educate on the subject of RAID. The RAB has developed specifications for RAID, a conformance program for the various RAID levels, and a classification program for RAID hardware.

Currently, seven standard RAID levels are defined by the RAID Advisory Board, called RAID 0–6. RAID typically is implemented by a RAID controller board, although software-only implementations are possible (but not recommended). The levels are as follows:

RAID Level 0—Striping. File data is written simultaneously to multiple drives in the array, which act as a single larger drive. Offers high read/write performance but very low reliability. Requires a minimum of two drives to implement.

RAID Level 1—Mirroring. Data written to one drive is duplicated on another, providing excellent fault tolerance (if one drive fails, the other is used and no data lost), but no real increase in performance as compared to a single drive. Requires a minimum of two drives to implement (same capacity as one drive).

RAID Level 2—Bit-level ECC. Data is split one bit at a time across multiple drives, and error correction codes (ECCs) are written to other drives. Intended for storage devices that do not incorporate ECC internally (all SCSI and ATA drives have internal ECC). Provides high data rates with good fault tolerance, but large numbers of drives are required, and no commercial RAID 2 controllers or drives without ECC, that I am aware of, are available on the market.

RAID Level 3—Striped with parity. Combines RAID Level 0 striping with an additional drive used for parity information. This RAID level is really an adaptation of RAID Level 0 that sacrifices some capacity, for the same number of drives. However, it also achieves a high level of data integrity or fault tolerance because data usually can be rebuilt if one drive fails. Requires a minimum of three drives to implement (two or more for data and one for parity).

RAID Level 4—Blocked data with parity. Similar to RAID 3 except data is written in larger blocks to the independent drives, offering faster read performance with larger files. Requires a minimum of three drives to implement (two or more for data and one for parity).

RAID Level 5—Blocked data with distributed parity. Similar to RAID 4 but offers improved performance by distributing the parity stripes over a series of hard drives. Requires a minimum of three drives to implement (two or more for data and one for parity).

RAID Level 6—Blocked data with double distributed parity. Similar to RAID 5 except parity information is written twice using two different parity schemes to provide even better fault tolerance in case of multiple drive failures. Requires a minimum of four drives to implement (two or more for data and two for parity).

Additional RAID levels exist that are not supported by the RAID Advisory Board but which are instead custom implementations by specific companies. Note that a higher number doesn't necessarily mean increased performance or fault tolerance; the numbered order of the RAID levels was entirely arbitrary.

At one time virtually all RAID controllers were SCSI based, meaning they used SCSI drives. For a professional setup, SCSI RAID is definitely the best choice because it combines the advantages of RAID with the advantages of SCSI—an interface that already was designed to support multiple drives. Now, however, ATA RAID controllers are available that allow for even less expensive RAID implementations. These ATA RAID controllers typically are used in single-user systems for performance rather than reliability increases.

Most ATA RAID implementations are much simpler than the professional SCSI RAID adapters used on network file servers. ATA RAID is designed more for the individual who is seeking performance or simple drive mirroring for redundancy. When set up for performance, ATA RAID adapters run RAID Level 0, which incorporates data striping. Unfortunately, RAID 0 also sacrifices reliability such that if one drive fails, all data is lost. With RAID 0, performance scales up with the number of drives you add in the array. If you use four drives, you won't necessarily have four times the performance of a single drive, but it can be close to that for sustained transfers. Some overhead is still involved in the controller performing the striping and issues still exist with latency—that is, how long it takes to find the data—but performance will be higher than any single drive can normally achieve.


Cheers


Moderator's can delete this if this is nor permitted.
 
Old 02-27-2006, 06:16 AM   #7
spoody_goon
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Great read thanks!
 
Old 02-27-2006, 06:25 AM   #8
asimba
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Quote:
Originally Posted by spoody_goon
Last question,
If I am looking for raid-0 hardware via pci, is there a big difference between the cheep raid cards ($69) and the expensive raids ($269)



Having 2 different sizes of hard drives 1-40 gig and 1-120 gig it sound like a raid is not for me. Do you agree?

Thanks

you can use RAID 0 (Hardware/SOftware implemented)
When it comes to RAID 1 - Software -Yes - and as far as hardware goes it depends on vendor's exact implementation . But you should be able to use small hard drive as Main one and larger as mirrored one where you loose whooping 80 Gigs .


Moreover New chipsets have kinda cheap RAID on motherboard itself.

Last edited by asimba; 02-27-2006 at 06:27 AM.
 
Old 02-27-2006, 06:37 AM   #9
spoody_goon
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Quote:
Originally Posted by asimba
Moreover New chipsets have kinda cheap RAID on motherboard itself.
Is that what is ment by "onboard serial ata" and "controller integrated"?

P.S. my mainboard is a k8m800-m7a
 
Old 02-27-2006, 06:47 AM   #10
asimba
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Quote:
Originally Posted by spoody_goon
Is that what is ment by "onboard serial ata" and "controller integrated"?

P.S. my mainboard is a k8m800-m7a
http://www.directron.com/directron/k8m800m7a.html

If this is what is being discussed then yes -


SATA: VIA VT8237R SATA RAID (RAID 0, 1). Up to 2 SATA devices.

you do not need to purchase RAID hardware - its already there. you just need to plug in the hard drives.

And as far as configuring different sized hard drives goes - Need to check out via website --- provided information above is right.
 
Old 02-27-2006, 07:01 AM   #11
spoody_goon
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Yep that is it. Thanks I have a hour or two until the hard drives are erased so I can begin working with the raid. You have been a great help, I will post back if there are any problems to ask for help if needed. I think you have given me all the inforamtion I need, but ya never know.

Thanks again
 
Old 02-27-2006, 07:32 AM   #12
asimba
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Quote:
Originally Posted by spoody_goon
Yep that is it. Thanks I have a hour or two until the hard drives are erased so I can begin working with the raid. You have been a great help, I will post back if there are any problems to ask for help if needed. I think you have given me all the inforamtion I need, but ya never know.

Thanks again

Sure bud, am glad if could help you.
In the mean time I will see I can find more information.
 
Old 02-27-2006, 08:50 AM   #13
spoody_goon
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Well that didn't take long... I am using Western Digital hard drives. Do you know what the jumper settings need to be? I am by the way searching for answers using google, you seem to be faster though.
 
Old 02-27-2006, 10:27 AM   #14
spoody_goon
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Ya know what, I don't have a SATA hard drive I have a EIDE hard drive. I'm sorry that my hardware knowedge is not very good. But I do believe I have been waisting your time. Well not a waist, I learn what a the difference between a SATA drive and an EIDE drive is. Next time I will know better what questions to ask.

opps
 
Old 02-27-2006, 08:01 PM   #15
asimba
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Quote:
Originally Posted by spoody_goon
Ya know what, I don't have a SATA hard drive I have a EIDE hard drive. I'm sorry that my hardware knowedge is not very good. But I do believe I have been waisting your time. Well not a waist, I learn what a the difference between a SATA drive and an EIDE drive is. Next time I will know better what questions to ask.

opps
Thats ok - as long as you get it working the way you want to - Cheers
 
  


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