Apple DU vs SoftRAID's drivers for RAID volumes: performancewise?

[hairypoo]

Hi,

For some time I have been using SoftRAID's (http://www.softraid.com/) drivers (v. 4.0.7) for an OS+apps SSD and my users' accounts on a 2*2TB RAID0 (WD Caviar Blacks) volume. At present the User volume is about 50% full (2 of 4TB).

I am considering to make the users' accounts volume a 2*3TB RAID1 (Hitachis) for safety reasons. My questions to the knowledgable people in this forum are:

1) I am aware that a RAID1 will be slower than a RAID0 volume. But will an Apple DU RAID1 or a SoftRAID RAID1 volume likely be faster?

2) Using SoftRAID's drivers on disks/volumes prohibits use of some troubleshooting utilities such as iPartition, DriveGenius, etc. Hence, is it adviseable to put SoftRAID drivers also on non-RAID volumes, such as my SSD boot volume?

I am hoping somebody with experience in these things can advise.
Thanks.

 

[derbothaus]

Hi,
2) Using SoftRAID's drivers on disks/volumes prohibits use of some troubleshooting utilities such as iPartition, DriveGenius, etc.

This is a good thing. Those apps are flakey at best.

Usually people get SoftRAID because they need RAID levels that Apple does not allow/ support in Disk Utility. Speed and overhead is very close as they are both SW RAID. For a real difference you need a hardware RAID controller.

 

[nanofrog]

For these particular levels (0/1), even hardware has limitations on performance.

Specifically, the read performance is ~ the same. But it will do better for write performance due to the write cache located on the hardware RAID controller (write cache either soldered to the card or via a DIMM slot). But it's expensive for this reason alone (there are other reasons running a hardware controller is valid for levels like RAID 1 <think OS/applications disk in a server>, such as recovery, but this isn't based on throughputs).

So port counts are the only reason that you'd want to go this route (more than the ICH and what inexpensive SATA cards can provide; shifting to a SAS based hardware controller can allow up to 256 disks on a single card via SAS expanders).

 

[hairypoo]

Thanks both for your helpful comments.

 

[smayer97]

I have used both extensively.

For the simple set up you are planning Apple's DU is more than adequate.

Both Apple and SoftRAID (v4.0+) have very similar performance. Reliability for Apple DU is ONLY good the version that comes with Snow Leopard onward. Any version prior to this is very flaky, especially if you end up using it to make a lot of changes.

I like to optimize the speed of my drives by isolating the first portion of the drive and installing the data that require the fastest access and use RAID 0 (partitions are created from the outer edge of a disk platter to the inner edge. Outer edge has significantly greater throughput).

The balance of the drives I partition and create RAID 0 or RAID 1's based on my data safety vs speed needs. I use one internal and 3 external drives, separating data from OS, using a bootable RAID partition for maintenance with my software Toolkit, some for Time Machine, and many for mirrors and back-ups of critical set-ups for quick recovery (using RAID 1 and CCC).

TIP: if you do desire to use RAID and PARTITIONS and want control over where your partitions are created on the disks, I have found the best way to do it is to use Apple DU to create the partitions first. Then use SoftRAID and convert the Apple Partitions to SoftRAID partitions, then create your RAIDs using SoftRAID. The reason is that SoftRAID does not give you control as to where your partition will be created, nor can you determine their location using SoftRAID's graphical presentation. SoftRAID works fine if you carefully plan ahead but if you decide to change your partitions, Apple DU gives you much better control.

The big advantage of SoftRAID over Apple DU is that RAID 1 mirror rebuilds are MUCH faster. And on today's large capacity drives, this can be very useful.

But again, based on your stated plan, Apple DU will do you fine.

If you still want to use SoftRAID (since you already have it), use TechTool Pro and/or SpeedTools Pro. These are more than adequate (some swear by DiskWarrior also).

 

[hairypoo]

Thanks, Smayer97, for your detailed information.