Raid 5 My Shuttle?

[gamesaregood]

Hello Everyone,

I currently have three drives in my SN25P:

74gb 8mb Cache Raptor
160gb Maxtor
320gb Seagate 7200.10

I'm considering swaping the Raptor and Maxtor for 2x more seagates and Setting up Raid 5 for Failover reasons, am i going to lose any / much speed over the single raptor that i currently use as my Windows Vista Boot Drive?

How does SATA Raid 5 inform you that a drive has failed and need replacing?

Thanks,

Michael

 

[rpstewart]

I take it you're planning on using the onboard RAID5 capabilites?

In that case I wouldn't recommend it - the nForce RAID controller relies on the main CPU to do all the XOR parity calculations for RAID5. This means that any writes to the disk are slow (15-20Mb/s) and are accompanied by high CPU load. If the array is going to be your only drive in the machine then this will really be noticable, all your normal writes will be slow and task switching will be excruciating as stuff is written to the swap file. Reads will be fine but the system will feel significantly slower than your current setup.

How does SATA Raid 5 inform you that a drive has failed and need replacing?

The NVRaid software monitors the array all the time and will alert if it goes critical.

 

[stoofa]

RAID 5 is designed to increase read performance and to offer redundancy across the whole array.
You will lose the equivalent of a disks worth of capcity over your three disk array.
You are actually losing a third of each disk for parity reasons.
So 3x 250GB HD's for example will give you 500GB of space you can use.
From a redundancy point of view you would be able to lose any one of the HD's and the remaining two, although at critical status, would be able to continue.
Replace the failed unit and array recovery could take place while the machine continues to run.
RAID 5 usually appears in servers as there is a definite increase in reading performance - which is what you require in a corporate environment.
Many users will want to be reading from a server at the same time, writing back isn't so common.

However - using a software RAID 5 or "Home User" RAID controller for RAID 5 I'm not convinced is the way forward.
CPU overhead would be high and I'm also not convinced by performance.
All of the servers that we use with a RAID 5 array have proper RAID 5 hardware controllers in with built-in cache.
This gives us maximum performance in all situations whilst keeping all the work away from the CPU.