RAID0: Will It Make THAT Much Difference?

[Marc]

I just upgraded to an A7N8X-E Deluxe. Right now, I'm using 2 ATA drives.
Somewhere down the road, I may consider buying a pair of SATA drives and run
them in a RAID0 configuration for speed. My question is this: Will I see a
significant increase in loading time for programs, or is this one of those
things that only a benchmark test will be able to measure?

Also, just to be sure I understand the concept...
2 x 80gig drives with RAID0 = 160gig of storage
2 x 80gig drives with RAID1 = 80gig of storage
Right?

My present setup...
A7N8X-E Deluxe
Athlon XP 1700+
ATI 9600XT
1 stick 512mb, 1 stick of 128mb (both 2700)
1 ATA 40 gig
1 ATA 80 gig

Thanks,
Marc

 

[Rob Stow]

I just upgraded to an A7N8X-E Deluxe. Right now, I'm using 2 ATA drives.
Somewhere down the road, I may consider buying a pair of SATA drives and run
them in a RAID0 configuration for speed. My question is this: Will I see a
significant increase in loading time for programs, or is this one of those
things that only a benchmark test will be able to measure?

Note that reads from a mirror are striped, so that you still get
all of the faster reading advantages that you would get from a
two-drive stripe set. RAID1 only offers a speed advantage
over RAID0 when data is begin written to the drives.

Also, just to be sure I understand the concept...
2 x 80gig drives with RAID0 = 160gig of storage
2 x 80gig drives with RAID1 = 80gig of storage
Right?

Yup. But with RAID 0, if you lose one of the drives you
lose *everything*. And because there are two drives that
might fail, the chances of losing everything are twice as
high as if you had a single drive.

With a mirror, if you lose one drive you still have a copy
of everything on the other drive.

 

[Leythos]

Note that reads from a mirror are striped, so that you still get
all of the faster reading advantages that you would get from a
two-drive stripe set. RAID1 only offers a speed advantage
over RAID0 when data is begin written to the drives.

RAID 0 provides faster writes, RAID 1 provides faster (almost as close)
READS as RAID 0. RAID 1 takes longer because it must control the
duplication of data on two drives, where RAID 0 just writes to the next
block on the next drive in the sequence, it doesn't duplicate anything.

Yup. But with RAID 0, if you lose one of the drives you
lose *everything*. And because there are two drives that
might fail, the chances of losing everything are twice as
high as if you had a single drive.

With a mirror, if you lose one drive you still have a copy
of everything on the other drive

This is the think that most people overlook - there is little
performance gain in RAID 0 unless using high-end IDE cards or SCSI
systems and with fast drives. The newer SATA drives rival even the SCSI
systems for performance when it comes to RAID arrays.

In most cases, and I've not seen any in real life for home users, RAID 0
just creates problems when they have a drive go bad.

 

[Doug Ramage]

In most cases, and I've not seen any in real life for home users, RAID 0
just creates problems when they have a drive go bad.


--

Yes, good back ups are essential - and I keep my data on a separate hard
drive. I can restore my RAID0 array in about 30 minutes.

 

[Marc]

Yes, good back ups are essential - and I keep my data on a separate hard
drive. I can restore my RAID0 array in about 30 minutes.

Back to the speed issue...
What gains are to be had with either RAID configuration? Theoretically, you
would expect twice the read speed over single drive setups. What are the
real world gains? 80%? 20%?

Marc

 

[Courseyauto]

50%

 

[CSX]

40%

Back to the speed issue...
What gains are to be had with either RAID configuration? Theoretically, you
would expect twice the read speed over single drive setups. What are the
real world gains? 80%? 20%?

Marc

 

[Barry Watzman]

Just understand that with many of the RAID controllers, whatever happens
to the operating speed, your boot time may increase dramatically, by 15
to 30 seconds.

 

[ToastFord]

Just understand that with many of the RAID controllers, whatever happens
to the operating speed, your boot time may increase dramatically, by 15
to 30 seconds.

If you RAID two drives, you no longer have two independant logical drives,
just one, and a single drive will work through a glut of i/o requests like
bootup or program opening, slower than two drives will (if the files can be
distributed between them).

It could make better use of an extra drive to offload swapfile and
application data to it, than RAIDing it at the hip to boost another~

 

[Barry Watzman]

Your post misses the point.

The BIOS on many (I'd really say most) raid systems takes a full 20 to
30 seconds during post to "discover" and configure the RAID array.
There is no actual disk I/O going on at all, it's all "overhead", but
it's VERY real, and VERY painful.

 

[Tim]

Barry,

If the only reason for getting raid was to reduce boot time, then your point
would be a show stopper. Intel ICH5R adds only a few seconds to boot at most
once configured and is one of the better ones.

Now, why do you want raid? Resilience? Thats worth paying for.

- Tim

 

[John]

Back to the speed issue...
What gains are to be had with either RAID configuration? Theoretically, you
would expect twice the read speed over single drive setups. What are the
real world gains? 80%? 20%?

Marc

I installed RAID 0 on a friend's PC and we ran benchmarks before and after
RAID 0 installation.

Boot up time - no difference (except extra time loading bios)
Load time for applications - no difference
Time to copy large files/folders - twice as fast using RAID

RAID is very good for people who work with large files (eg. editing video)

 

[ToastFord]

Your post misses the point.

The BIOS on many (I'd really say most) raid systems takes a full 20 to
30 seconds during post to "discover" and configure the RAID array.
There is no actual disk I/O going on at all, it's all "overhead", but
it's VERY real, and VERY painful.

Very Painful !blip... 'come on, come On Hurry Up!'
I can appreciate its annoying, but reboot so rarely I enjoy the time-out
The most significant drawback from using raid that I suppose - is that you
have to sacrifice a whole extra drive for it.

A virtual device driver which could use partitions of separate drives, to
make a drive-spanning virtual partition, of extra speed or security, would
be nice~

 

[Noozer]

This is the think that most people overlook - there is little
performance gain in RAID 0 unless using high-end IDE cards or SCSI
systems and with fast drives. The newer SATA drives rival even the SCSI
systems for performance when it comes to RAID arrays.

RAID 0 can increase performance (and I'd guess around 30%) over a single
drive, but you get much better "snappiness" of the PC if you have your
system drive and data drive separate. This allows Windows to swap to the
hard disk for memory cache without being bogged down by your email software
loading the mailbox or CD Burning caching files etc. Partitioning a single
drive into multiple drives will NOT help with speeds.

With three drives you probably should RAID the system drive, but it seems a
waste considering how much space system files take and the size of hard
drives these days. Ideal would be a pair of 34gig Raptor drives in RAID0 for
system files and a 74gig Raptor for data.

It would be very cool if HD manufacturers could implement an independent
head/platterside on the hard drives that could be used for fast access data
like swapfile, etc.

Another idea would be dual SATA data connectors and two sets of heads in a
single drive and a LARGE memory cache. Reads/writes could be independent and
you could still have RAID0 with a single drive unit.

 

[Doug Ramage]

My SATA drives needed the RAID controller enabled, even without an array.
Extra boot time about 3 seconds; re-boot time about 1 second.

Changing the Maxtor SATA drives to 2 x Raptors in RAID0 made NO difference
to boot/re-boot times.

 

[Tim]

Dear Toast,

If your computer is for busines then the cost of a second drive is surely
less than the cost of rekeying in your data.

Take a look at RAID 10.

Windows NT onwards has built in fault tolerant driver where you can create
mirrored and striped soft-raid volumes. With XP I believe you can also have
mirrored boot volumes using s/w raid.

- Tim

 

[Andrew J]

Back to the speed issue...
What gains are to be had with either RAID configuration?

9 out of 10 SOHO users using RAID use RAID 0 since it offers some
performance boost when working with very large files. Every day
computing shows no change in performance. Some benchmarks show lower
performance in some cases for everyday use. These hits are very hard
to detect and might really just be from problems with the testing
programs.

Theoretically, you
would expect twice the read speed over single drive setups.

The most important thing to SOHO users is seek time. RAID has no
improvement in that catagory, ever. The 10,000 RPM SATA drives have a
very fast seek time so would help most users more than any RAID setup.

What are the
real world gains? 80%? 20%?

Real RAID 0 gains are noticed only when working with 50MB-100MB files
or larger. Just moving/deleting old video footage goes much faster.
Loading a game level very fast is another bonus.

 

[ToastFord]

Dear Toast,

If your computer is for busines then the cost of a second drive is surely
less than the cost of rekeying in your data.

Hi Tim, I see its not an expensive setup, and fault tolerance very
desirable.

Take a look at RAID 10.

Ive gotten used to a plain Dual Drive setup, and manual backups. OS & Progs
work faster with two drives than one if major folders and files are spread
between them. I notice how, the performance gains offered by Raid setups
could be more fairly compaired against the performance of two drives
- Intresting to see sysperf benchmarks of Raid setups, compared to an
optimised 2 Drive setup.

Windows NT onwards has built in fault tolerant driver where you can create
mirrored and striped soft-raid volumes. With XP I believe you can also have
mirrored boot volumes using s/w raid.

Not far off maybe >
Thinking of Raid as the theory used by kinds of virtual drive drivers,
seems kinda simple to just stripe and mirror - maybe theres no gains in
making it more complex.
I havent investigated the options myself, the usual performance figures
dont sound that enticing to me, except the fault tolerance option.

cheers,
toast

 

[Milleron]

Barry,

If the only reason for getting raid was to reduce boot time, then your point
would be a show stopper. Intel ICH5R adds only a few seconds to boot at most
once configured and is one of the better ones.

Now, why do you want raid? Resilience? Thats worth paying for.

- Tim

Not sure what's meant by "resilience," so I don't necessarily mean to
disagree, but by my definition, RAID 0 detracts from resilience by
doubling the chance of a hard drive failure. RAID 1can give some
resilience, but, because of latency inherent in the controller, it
detracts a little from performance.
My standard response to threads like this is that if one is a home PC
user not using your computer for frequent video editing, don't set up
a RAID 0. If one needs performance, get a 10,000 rpm Raptor. If one
needs protection against HD failure, set up a RAID 1.
I have RAID 0 now, and I consider it a waste of money. My next
homebuilt will have my OS(s) on a Raptor and everything else on a
second drive with a third very large HDD for frequent Drive-Image or
Ghost backups.
Ron