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How to combine harddisks for performance (no raid)

Last response: in Storage
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May 28, 2010 12:54:37 PM

I need to write multple jpeg streams constantly totalling up to 20 or even 25 mb/second. A fraction of a second system freeze means data is gone. I want to be safe so no RAID setup and want to minimize noise and heat.

I planned using a 600 GB WD Velociraptor for data because of the speed (and also put a small startup partition on it) and a 2TB Caviar green for long term storage.

For the same money I could buy a small SSD for OS + programs and two (or three) 2TB Caviar green disks. Those should run at about the same noise level and give me fast OS statup. But how does data writing performance compare?

The data streams to be ritten could be split over two disks. According to http://www.tomshardware.com/reviews/wd6000hlhx-velocira... the specs are:

write accestime:
3,2 ms Velociraptor 600GB
6,9 ms caviar green 2TB

IOMeter:
296,4 Velociraptor 600GB
128,4 caviar green 2TB

SEQUENTIAL write performance (no random write performance available) eems to be:
Velociraptor 600GB 100mb/sec to 150mb/sec
caviar green 2TB 50mb/sec to 100mb/sec


Two questions com up:
(1) SSD's (regardless of prize) are said to give random system freezes of up to several seconds at a time. Will that also happen if data is stored on the HDD's and not on the SSD?
(2) How to estimate the combined performance of splitting data streams on two HDD's (caviar green) instead of one fast harddisk (velociraptor)?
a b G Storage
May 28, 2010 6:23:24 PM

There are safe raid setups, raid 1 or raid 10. raid 5 wouldn't be as good for high performance writes, though.

What OS are you planning on running this under?
May 28, 2010 10:33:16 PM

I used mirroring for years on a dedicated controller card. Uses up twice the harddisk capacity and doubles HDD noise.

I am planning to use windows 7 in 32 bit version and if that gives compatibility problems with programs I will go back to windows XP 32 bit version. Planning to use the new gigabit U7 motherboard and 3 GB ram.

I find it hard to judge how multiple data streams affect needed HDD specs.
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May 29, 2010 6:46:15 AM

WOW MRFS, those are some impressive charts.
Caviar black 2TB wins with a big margin. The WD RE4 really disapoint in that test. The caviar green holds up very well for a "green" drive.

Putting every stream on a different hdd would mean buying 6 caviar blacks. Seems like a noisy and expensive solution and I think will be overkill also.
May 29, 2010 1:52:45 PM

I recommend the Western Digital AV-GP series drives. They are designed for contast write 24/7 and has much higher reliability than normal consumer level drives.

They are a bit slow but that is the tradeoff but a constant data stream of 25mb/s is definitely cappable. You can get a couple of them for RAID 1 to get maximum security. RAID 10 has less security but more write performance. RAID 5 or 6 would have better write performance but lacks on read.
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