Promise RAID0

[iparout]

Hi there,

I am planning on buying a RAID 0 controller by promise (preferably the FastTrak100 TX 4), however I have a small question :

I am planning on buiyng ONE hard drive first (80 or 100 GB Western Digital) and connect it to the RAID controller until I buy the second harddrive to RAID them together.

MY QUESTION IS : How will the controller perform with only one HDD attached to it ? Will I see any speed gains or not ?

And also, when I connect 4 HDD to the TX4, will the speed become 4 times faster ?

Thx in advance.

P.S. : Does anyone know when the 100 GB 7200 Hard drives will be out ?

P.S 2 : Which combo is better in terms of cost\performance ratio : A 4x60 GB RAID 0 or a 3x80 GB RAID 0 ?

[Job]

RAID is 2 or more drives...

You'll have an ATA100 controller only.
Read up on RAID and understand how it does 'da business.
You'll need 2 drives.

BTW Win2KPro hasa software based RAID config that will do
da business - so no need for the card. You just cant have the dual boot option with the RAID setup.

3 drives is faster again (about 100MBps sustained) but getting exxie $$$!
4 drives - not any faster....but usually 4 drive stripping is for backup - you only get 2xdrive capacity but that is mirrored on the second drives in case one goes.

my 2c

[MultimediaMan]

IDE RAID with the Promise TX4 and HPT370 will yield the fastest results with two drives, regardless of configuration. IDE drives are limited to One I/O operation per cycle: adding drives as slaves only slows the IDE interface.

All high-end IDE RAID (Promise Supertrack, Adaptec, et al..) solutions are limited to only single drives on each IDE channel.

SCSI on the other hand can REALLY make things move right along. A 3 channel SCSI RAID 5 array with 3,6,9 up to 45 drives is mind-bogglingly fast.

I've only actually SEEN a 3 channel raid array (RAID Level 5) with 15 drives in use, and it was mind-numbing how fast 8 gigs of data could be made to move across a Gigahertz network: I cannot being to guess how much faster a 45 drive array with the same hardware would have worked.

[Technoid]

I heard Dr. Mordrid talk about the Tx4...
And that one had 4 ide conectors enabling four drive and great speed !

[MultimediaMan]

The Promise Fastrack 100 is a dual channel solution: it can support 4 drives, but as Master and Slave. The only possible setups are RAID 0 (1-4 drives), RAID 1 (2 or 4 drives), RAID 0+1 (4 Drives).

The Promise Supertrack 100 comes in a couple of versions with 4 channel single drive or six channel single drive support for all common RAID Levels, Including RAID5.

Adaptec's 2nd Generation 4 channel IDE RAID controller is also a fine product and also supports all common RAID architectures, including RAID5.

Steer clear of the 1st Generation Adaptec IDE RAID controller: not only it is a kludge, it is actually SLOWER than most ATA66 chipsets out there.

[Chuckwagon]

iparout,

Running a single drive on your RAID controller will work fine. You won't get the performance gains you would see with multiple drives, but it won't suffer either. In some instances you may see better or worse performance than what you'd get off the integrated IDE, but that depends more on the chipsets involved and the drivers available than on the single drive configuration.

As for how your speed will be when connecting 4xHDDs to the RAID controller, it will likely be close to 4x the performance, but there are no guarantees. It will depend on the drives, the controller, the cpu, RAID configuration, and the workload used.

In general, when using an IDE RAID, single drives on each channel in a RAID 0 configuration will yeild your best performance. So you should be fine staring with one drive, and then adding individual drives to your remaining channels as you can.

As a side note, for anyone interested, generally speaking: RAID 0 is fastest, and RAID 5 is slowest. The other RAID flavors fall in between. RAID 5 writes parity info to EVERY drive in the stipe for EVERY write performed, thus adding dramatically to the overhead of each write, which is why it's slowest. RAID 5 does however offer you greater capacity with redundancy than RAID 1 would, but at the cost of speed. SCSI can be faster than IDE, depending on the SCSI format, but is almost always more expensive. Duplexed RAIDs will often outperform non-duplexed configurations, especially if you have a fast system bus, but cost much more. More channels equals higher performance potential. More spindals equals lower latency potential, and thus higher performance potential. Stripe SIZE will affect performance, and testing several stripe sizes on your config is reccomended. Cache on the controller also helps.

SCSI RAIDs perform at their best when using 3-4 drives per SCSI channel. In some instances 5 drives per channel yeilds peak performance, but most often it's 4 drives per channel that is the ticket. SCSI command overhead is the devil in the details here, which is why adding drives doesn't buy much after 4. From a cost standpoint though, 2 drives per channel is a better setup, as the performance gains you would see going from 2 to 3 then to 4 drives per channel often aren't worth the price. Especially if you have a multi-channel controller. You end up being better of adding drives to each available channel first before going with multiple drives on a channel.

Obviously these are generalizations, and specific configurations can be better or worse depending on design and the desired effects.

Hope that's helpful.

Chuck

[Dr Mordrid]

The Promise SuperTrak100 IS NOT an option for editing. It's sustained sequential throughput is not up to the FT100 or TX4 cards....not even close. Because of this the ST100 is more of a server solution due to its security and remote management features. It also only works in WinNT/2K/XP because of the requirement for I20 support.

I'm speaking from experience here as I tested the SuperTrak100 for Promise to see if it would be useful for video. It wasn't.

The TX4 is different situation entirely.

While the FT100/66/33 all used master/slave shared headers from a single controller ASIC the TX4 is different. It uses four master drive connects by way of two ASIC's. The dual ASIC's are interfaced using a PCI/66 bridge chip that also provides a PCI/33 compatability mode.

Because of its use of dual ASIC's the TX4 requires 2 IRQ's, but this doesn't matter much. It shares nicely. Mine shares with my RT2K's IEEE-1394 and the G400 Flex display adapter.

The performance differences (using four 75GXP's in a 240g array):

FT100 RAID0

1 drive: 1x single drive speed (natch)
2 drives: 2x single drive speed (2x capacity)
3 drives: 2.5-2.7 single drive speed (3x capacity)
4 drives: little additional speed gain, if any. (4x capacity)

The 3rd and 4th drive don't add as much speed as the 1st and 2nd because they are connected in a master/slave arrangement. As such only one drive at a time on a given channel can be writing, the other has to wait its turn thus reducing the maximum throughput to well below the theoretical max levels.

FT TX4 RAID0

1 drive: 1x single drive speed (natch)
2 drives: 2x single drive speed (2x capacity)
3 drives: 2.9x single drive speed (3x capacity)
4 drives: 3.8x single drive speed (4x capacity)

Because of its 4 master setup each drive can be written to without any of the others having to be in a wait state. As a result throughput is maximized.

Uppance:

95-102 mb/s sequential writes & over 100 mb/s sequential reads in Win98SE/FAT32 using a PCI/33 slot. Slightly less in Win2K/NTFS.

Dropped frames? What are they?

Any questions?

Dr. Mordrid

[iparout]

Well, as I originally said I'll probably buy the FastTrack TX4, so I guess there's not that slave\master problem.