Add-on RAID

[Robert]

I have an Asus P4PE mother board - the version without Raid. I have
decided to increase my storage capacity and add Raid 1. I was thinking
of retaining my existing ATA disk with winXP and applications on with
its current primary IDE connection, and adding a SATA Raid card with a
pair of Seagate/Samsung SATA 160Mb disks to handle the data storage.
The only reason for starting to go over to SATA now for the new HDDs is
that it may help further down the line when I do a motherboard upgrade.
Grateful for any thoughts or comments.

 

[Ruel Smith]

I have an Asus P4PE mother board - the version without Raid. I have

decided to increase my storage capacity and add Raid 1. I was thinking of
retaining my existing ATA disk with winXP and applications on with its
current primary IDE connection, and adding a SATA Raid card with a pair of
Seagate/Samsung SATA 160Mb disks to handle the data storage. The only
reason for starting to go over to SATA now for the new HDDs is that it may
help further down the line when I do a motherboard upgrade.
Grateful for any thoughts or comments.

RAID 1, while working well for backup, will significantly slow your disk
access, and therefore your system, down. Also, Depending on how soon you're
planning on upgrading, your 160GB disks may seem puny by the time you
upgrade.

 

[John Weiss]

RAID 1, while working well for backup, will significantly slow your disk
access, and therefore your system, down.

Not necessarily true...

While software RAID solutions will slow down a system, hardware RAID
controllers do not have that problem in general. My SATA RAID 1 system is
slower than RAID 0, but no slower than baseline (no RAID).

Just remember that any PCI-based RAID solution will be limited by the PCI
bus speed. A normal 32-bit PCI bus maxes out at 133 MBps, but that is not a
problem with a single pair of HDs in RAID 0 or RAID 1. Even the fastest
RAID HDs max out around 70 MBps, and sustained throughput in RAID 0 is more
like 50-60.

 

[Ruel Smith]

RAID 1, while working well for backup, will significantly slow your disk

Not necessarily true...

While software RAID solutions will slow down a system, hardware RAID
controllers do not have that problem in general. My SATA RAID 1 system is
slower than RAID 0, but no slower than baseline (no RAID).

If you're going to invest in a high-end add-on card, maybe, since they have
dedicated processors of their own. However, there is still some overhead in
writing the same info to two disks at the same time and I have a hard time
believing that it won't slow it down at all. The problem with all of this is
that there lacks a true accurate way of comparing disk performance. I
remember just a couple of years ago where people raved about a certain hard
drive benchmark software and MaximumPC ran a test using it and discovered
that a single disk was faster than RAID 0 for short file access. Well, a
bunch of readers wrote in and informed them of the shortcomings of the
benchmark software and they had to retest using some kind of RAM disk setup
to eliminate the bottleneck causing the skewed results. When those results
came in, RAID 0 kicked the living daylights out of a single drive in every
catagory. Still, many believe it's not that much faster than a single drive,
and certainly not enough to justify the added risk of losing data or the
complexity of it. The jury is still out. I, however, swear by it.

Just remember that any PCI-based RAID solution will be limited by the PCI
bus speed. A normal 32-bit PCI bus maxes out at 133 MBps, but that is not
a problem with a single pair of HDs in RAID 0 or RAID 1. Even the fastest
RAID HDs max out around 70 MBps, and sustained throughput in RAID 0 is
more like 50-60.

I can't remember if it was Tom's Hardware or another site that put together
an ATA133 RAID 0 setup a few years back, when it was all the rave, using
onboard Promise and Highpoint controllers, and add-in cards from both. They
attained a sustained 119 MB/s using 4 hard drives with the add-in Promise
card and nearly the same with both the add-in and onboard Highpoint. The
onboard Promise was limited to 2 drives.

 

[John Weiss]

If you're going to invest in a high-end add-on card, maybe, since they
have dedicated processors of their own. However, there is still some
overhead in writing the same info to two disks at the same time and I have
a hard time believing that it won't slow it down at all. The problem with
all of this is that there lacks a true accurate way of comparing disk
performance.

....and also that most people seeking advice on this forum will not be able
to measure any performance differences subjectively, lacking the benchmark
software.

I can't remember if it was Tom's Hardware or another site that put
together an ATA133 RAID 0 setup a few years back, when it was all the
rave, using onboard Promise and Highpoint controllers, and add-in cards
from both. They attained a sustained 119 MB/s using 4 hard drives with the
add-in Promise card and nearly the same with both the add-in and onboard
Highpoint.

That's about right, averaging 30 MBps per HD in RAID 0. I suspect that was
also with no other traffic (Ethernet, modem, sound, USB, etc) on the PCI
bus, though...