due to my never ending need for more storage i looked for a good raid controller but the i saw this:
http://www.sata-io.org/portmultiplier.asp
http://www.cooldrives.com/cosapomubrso.html
http://www.addonics.com/products/host_c ... d5sapm.asp
5 sata in the price of one port... i can live with that.
but is it a good solution?
SATA Port Multiplier, does it work?
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JazzJackRabbit
- Posts: 1386
- Joined: Fri Jun 18, 2004 6:53 pm
I've looked into those some time ago for the same reason as you did and as far as I understand this is a bad solution because essentially you'll be having JBOD array of 5 drives. You lose one drive you lose data on all 5 of your drives. Really bad.
In corporate environment this might not be a problem because they might hook up 4 of those port multipliers each with 5 drives attached and hook them up in RAID 5 on port multiplier level, but I highly doubt you're gonna do this.
In corporate environment this might not be a problem because they might hook up 4 of those port multipliers each with 5 drives attached and hook them up in RAID 5 on port multiplier level, but I highly doubt you're gonna do this.
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lowpowercomputing
- Posts: 154
- Joined: Fri Dec 23, 2005 3:05 am
- Location: Germany
As far as I understand it, a controller that supports Port Multipliers will see every drive attached to it as a single one, i.e. there's no "internal array" or JBOD at all. You just need a controller that supports port multiplying. Quote from SATA-IO:
"The port multiplier is transparent to the drives. The host knows that it is communicating to multiple drives, but the drives are unaware that they are being multiplexed. The SATA drives function as if they were directly attached to the host adapter. Port multipliers support any standard SATA drive."
This port multiplier by CoolGear is internally doing a RAID/JBOD, so that's probably not what you want. A normal multiplier doesn't do that.
"The port multiplier is transparent to the drives. The host knows that it is communicating to multiple drives, but the drives are unaware that they are being multiplexed. The SATA drives function as if they were directly attached to the host adapter. Port multipliers support any standard SATA drive."
This port multiplier by CoolGear is internally doing a RAID/JBOD, so that's probably not what you want. A normal multiplier doesn't do that.
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JazzJackRabbit
- Posts: 1386
- Joined: Fri Jun 18, 2004 6:53 pm
Didn't know that, thanks for the info.
Although I still think that port multiplier uses are limited. If you are not doing RAID buying dumb 8 port SATA2 controller like this (which should work in 32bit slot as well) is going to be cheaper considering you don't have to buy multiplier-aware controller as well as proper port multiplier which is going to be expensive. If you are doing raid port multipliers will probably kill a lot of performance because you will be multiplexing lots of drives on single SATA2 channel. You might as well go for the same SuperMicro controller and do software RAID5 using either Windows Server or Linux. Or you could go with hardware RAID5, Adaptec 3805 is going for $375 on ewiz, just a word of caution, they run HOT, they WILL need active cooling.
Although I still think that port multiplier uses are limited. If you are not doing RAID buying dumb 8 port SATA2 controller like this (which should work in 32bit slot as well) is going to be cheaper considering you don't have to buy multiplier-aware controller as well as proper port multiplier which is going to be expensive. If you are doing raid port multipliers will probably kill a lot of performance because you will be multiplexing lots of drives on single SATA2 channel. You might as well go for the same SuperMicro controller and do software RAID5 using either Windows Server or Linux. Or you could go with hardware RAID5, Adaptec 3805 is going for $375 on ewiz, just a word of caution, they run HOT, they WILL need active cooling.