• Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
    Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.

Raid 1 - Three Disks, Double Redundancy Help

Q

Quanticles

Limp Gawd
Joined
Feb 25, 2005
Messages
139
Hi,

My computer can hold 3 harddrives. I would like to have some redundancy for my system, but I would also like to have a large amount of space. Ideally I would like to be able to run Raid 1 with three disks, but have only double redundancy. Meaning, I would like to combine three 500GB harddrives and get 750 MB of space out of it. Does anyone know if this is possible?

If the disks were broken into 250mb halves. Disk 1 would mirror one half with Disk 2, and one half with Disk 3.

I know there is Raid 5 that works with three disks, but I dont think the performance would be as good as this, since it requires a large amount of calculation for writes, and each block is only available on one disk (no mirroring). On the other hand, it would allow me to have a full terabyte of data.

Any ideas?

Thanks
 
This was actually meant to be a question. Can an admin add "Help:" or "Question:" to the thread title?

Thanks
 
If your looking to make one large drive then you will have to stripe. if you want to have data redundency you will have to mirror. You can allways stripe and mirror but that is a minimum of 4 drives of which you loose two to redundency. Raid 5 requires the same 4 drives but you only loose one for your paridy bit. Raid five is the way to go and is no slower than raiding 3 drives consecutively.


BTW if you have never raided drives before, you probably wont see a huge speed boost with striping drives. There is noted increase but nothing to go crazy about.
 
Raid5 is what you want. It should be significantly faster than Raid1. Raid5 has a lower I/O rate, but thats only really important for high end databases, home users usually need higher sustained transfer rates for better performance. Remember the disks themselves are the bottleneck point, usually not the controller.
 
IBM controllers (and many others) do something called "Raid 1E" which does what you want. It works like this:
Code: 
Disk: 1  2  3
      A  A  B
      B  C  C
      D  D  E
      E  F  F
So each block is written twice over as many disks as you add to the set. That way there are two copies of everything, and you get half the storage space.

I don't know of any cheap controllers that do this, despite it being a relatively simple thing to do. LSI does it on their low-end SAS cards, for example the LSISAS3041E-R. It's pretty expensive for a 4-port card, though - around $225 seems to be the going rate for a merchant I recognize.
 
Thanks guys!

I'm using an NF4-SLI board, which the tech specs say supports RAID 0, 1, 5, and 0+1. If it supports 1E that will be sweet. If not, 5 will be cool
 
got the same board. 5 is the way to go to maximize speed and ridundancy while minimizing loss of space
 
yes RAID-5 is a ways to increase uptime, with a small loss in space and a l(small/medium/large) loss in write performance.
 
You must log in or register to reply here.
Back
Top