Use RAID 1, and P5B onboard controller? Disk failing, need input on options

I have a P5B Deluxe which includes on board sata raid, which I
understand to be more or less a software raid soultion and therefore
maybe not as efficient as hardward raid. The system boots from a WD 40g
raptor and has a maxtor 500gb disk for most of my work stuff
(programmer). The year old maxtor disk fails to show up at boot
sometimes and can also go in the middle of work; I've swapped sata
cables and it still fails sometimes.

I've never used raid, but am staring to consider it now. Would a
reasonable approach be to buy two 750 gb sata disks and use raid 1? I'd
remove both the raptor and the maxtor. I don't really fully get raid but
I think for use in a workstation raid 1 suits. I'm looking for data loss
prevention and for performance to improve or at least not degrade much.

Is raid 1 the way to go for a situation like this? raid 5 uses 4 disks
min and I'm not eager to run four disks all day.

Will removing the now-too-small-anyways raptor and using the raid array
for everything result in reduced performance?

As far as raid controllers go, should I skip the P5B onboard controller
and go with a pci card? There are some well rated raid cards on newegg
for $30 or so but not sure if needed or if a low price card will really
serve.

I know this topic is well worn but in this case I'm hoping to get some
input from more experience folks.

In article < >,
says...
> I have a P5B Deluxe which includes on board sata raid, which I
> understand to be more or less a software raid soultion and therefore
> maybe not as efficient as hardward raid. The system boots from a WD 40g
> raptor and has a maxtor 500gb disk for most of my work stuff
> (programmer). The year old maxtor disk fails to show up at boot
> sometimes and can also go in the middle of work; I've swapped sata
> cables and it still fails sometimes.
>
> I've never used raid, but am staring to consider it now. Would a
> reasonable approach be to buy two 750 gb sata disks and use raid 1? I'd
> remove both the raptor and the maxtor. I don't really fully get raid but
> I think for use in a workstation raid 1 suits. I'm looking for data loss
> prevention and for performance to improve or at least not degrade much.
>
> Is raid 1 the way to go for a situation like this? raid 5 uses 4 disks
> min and I'm not eager to run four disks all day.
>
> Will removing the now-too-small-anyways raptor and using the raid array
> for everything result in reduced performance?
>
> As far as raid controllers go, should I skip the P5B onboard controller
> and go with a pci card? There are some well rated raid cards on newegg
> for $30 or so but not sure if needed or if a low price card will really
> serve.
>
> I know this topic is well worn but in this case I'm hoping to get some
> input from more experience folks.
>
Another question...there is an choice to make re the boot drive.
Apparently I could keep a separate non raid disk for booting, or boot
from the raid array. Performance would be better with a distinct boot
disk but then it'd not be mirrored. Any comments?

nano wrote:
> In article < >,
> says...
>> I have a P5B Deluxe which includes on board sata raid, which I
>> understand to be more or less a software raid soultion and therefore
>> maybe not as efficient as hardward raid. The system boots from a WD 40g
>> raptor and has a maxtor 500gb disk for most of my work stuff
>> (programmer). The year old maxtor disk fails to show up at boot
>> sometimes and can also go in the middle of work; I've swapped sata
>> cables and it still fails sometimes.
>>
>> I've never used raid, but am staring to consider it now. Would a
>> reasonable approach be to buy two 750 gb sata disks and use raid 1? I'd
>> remove both the raptor and the maxtor. I don't really fully get raid but
>> I think for use in a workstation raid 1 suits. I'm looking for data loss
>> prevention and for performance to improve or at least not degrade much.
>>
>> Is raid 1 the way to go for a situation like this? raid 5 uses 4 disks
>> min and I'm not eager to run four disks all day.
>>
>> Will removing the now-too-small-anyways raptor and using the raid array
>> for everything result in reduced performance?
>>
>> As far as raid controllers go, should I skip the P5B onboard controller
>> and go with a pci card? There are some well rated raid cards on newegg
>> for $30 or so but not sure if needed or if a low price card will really
>> serve.
>>
>> I know this topic is well worn but in this case I'm hoping to get some
>> input from more experience folks.
>>
> Another question...there is an choice to make re the boot drive.
> Apparently I could keep a separate non raid disk for booting, or boot
> from the raid array. Performance would be better with a distinct boot
> disk but then it'd not be mirrored. Any comments?

If the Maxtor is running at SATA2 cable rates (3Gbit/sec), try
jumpering it for SATA1 cable rates (1.5Gbit/sec) instead. There may
be room for a jumper on the back of the drive, to control cable rate.
If the details are not on the drive label, check the Seagate website.
You can also get a diagnostic from the website, to test the disk.

I would not consider RAIDing that drive, until it performs reliability.
Or replace it with a drive that does work well.

With regard to your original question, RAID1 (mirror) is not a replacement
for backups. Say, for example, the power supply goes nuts, and delivers +15V
on the 12V rail. The motors on both drives in the mirror, get burned at the
same time. There are parts of the motherboard, that are common to both
drives. The RAID 1 part is only protecting against a subset of all possible
failure types. You could still lose all your data, so a backup should be
created, which is disconnected from the computer when not in use.

Using a RAID1, extends the period before maintenance has to be done on the
storage subsystem. For example, on a server, if a RAID1 degrades at lunchtime,
the staff can schedule maintenance for the evening. So the users are not
inconvenienced during the day. It is hard to say what a RAID1 desktop buys,
except as a crutch for less frequent backup strategies. You should still
be doing daily backups, because you could even have an operational error
(rm -R *). A mirror doesn't protect against accidental deletion.

Paul

In article <fs6c3n$v2j$>, says...
> nano wrote:
> > In article < >,
> > says...
> >> I have a P5B Deluxe which includes on board sata raid, which I
> >> understand to be more or less a software raid soultion and therefore
> >> maybe not as efficient as hardward raid. The system boots from a WD 40g
> >> raptor and has a maxtor 500gb disk for most of my work stuff
> >> (programmer). The year old maxtor disk fails to show up at boot
> >> sometimes and can also go in the middle of work; I've swapped sata
> >> cables and it still fails sometimes.
> >>
> >> I've never used raid, but am staring to consider it now. Would a
> >> reasonable approach be to buy two 750 gb sata disks and use raid 1? I'd
> >> remove both the raptor and the maxtor. I don't really fully get raid but
> >> I think for use in a workstation raid 1 suits. I'm looking for data loss
> >> prevention and for performance to improve or at least not degrade much.
> >>
> >> Is raid 1 the way to go for a situation like this? raid 5 uses 4 disks
> >> min and I'm not eager to run four disks all day.
> >>
> >> Will removing the now-too-small-anyways raptor and using the raid array
> >> for everything result in reduced performance?
> >>
> >> As far as raid controllers go, should I skip the P5B onboard controller
> >> and go with a pci card? There are some well rated raid cards on newegg
> >> for $30 or so but not sure if needed or if a low price card will really
> >> serve.
> >>
> >> I know this topic is well worn but in this case I'm hoping to get some
> >> input from more experience folks.
> >>
> > Another question...there is an choice to make re the boot drive.
> > Apparently I could keep a separate non raid disk for booting, or boot
> > from the raid array. Performance would be better with a distinct boot
> > disk but then it'd not be mirrored. Any comments?
>
> If the Maxtor is running at SATA2 cable rates (3Gbit/sec), try
> jumpering it for SATA1 cable rates (1.5Gbit/sec) instead. There may
> be room for a jumper on the back of the drive, to control cable rate.
> If the details are not on the drive label, check the Seagate website.
> You can also get a diagnostic from the website, to test the disk.
>
> I would not consider RAIDing that drive, until it performs reliability.
> Or replace it with a drive that does work well.
>
> With regard to your original question, RAID1 (mirror) is not a replacement
> for backups. Say, for example, the power supply goes nuts, and delivers +15V
> on the 12V rail. The motors on both drives in the mirror, get burned at the
> same time. There are parts of the motherboard, that are common to both
> drives. The RAID 1 part is only protecting against a subset of all possible
Hi Paul

Thanks for writing. I backup all of my data files regularly to external
hdd a couple times a week and online several times a day. Backups are
good! The raid consideration is to guard against a single disk going
out, to catch the interim updates. Also, if one disk starts to go out,
the system is not at risk, I'd need to troubleshoot or replace the
failing disk.

Still curious about a couple of things.

#1 raid 1 would likely be the best variant for my simple needs?
#2 is the p5b deluxe onboard raid controller ok, or should I buy a
controller?
#3 if I replace the raptor and my os/boot drive is a larger,
partitioned, raid 1 set, will performance suffer?
#4 not really sure about boot disk issue in general. If only two disks
in the box, if software raid, I think I need a c partition that is not
raid, to boot from, and other partitions would be in raid array?

I took the faltering maxtor out of the case and have it laying on it's
side next to the case; it's gone a day without issues. It couldn't be
overheating issue in case becase it has failed after long off periods;
cabling maybe, though I've changed them.

nano wrote:

> Hi Paul
>
> Thanks for writing. I backup all of my data files regularly to external
> hdd a couple times a week and online several times a day. Backups are
> good! The raid consideration is to guard against a single disk going
> out, to catch the interim updates. Also, if one disk starts to go out,
> the system is not at risk, I'd need to troubleshoot or replace the
> failing disk.
>
> Still curious about a couple of things.
>
> #1 raid 1 would likely be the best variant for my simple needs?
> #2 is the p5b deluxe onboard raid controller ok, or should I buy a
> controller?
> #3 if I replace the raptor and my os/boot drive is a larger,
> partitioned, raid 1 set, will performance suffer?
> #4 not really sure about boot disk issue in general. If only two disks
> in the box, if software raid, I think I need a c partition that is not
> raid, to boot from, and other partitions would be in raid array?
>
> I took the faltering maxtor out of the case and have it laying on it's
> side next to the case; it's gone a day without issues. It couldn't be
> overheating issue in case becase it has failed after long off periods;
> cabling maybe, though I've changed them.

One thing that bothers me about RAID, is the general inability to tell
when things aren't working right. Yes, a bad status on a drive, such
as a failure detected by the controller on the disk, would work OK.
But I'm thinking of more subtle failures.

To give an example, someone had a SIL3112 based RAID mirror they set up.
One day, one of the disks failed, leaving one working disk. The owner
of the system, discovered that the mirror disk, had stopped updating
like three months earlier, so in fact it wasn't a mirror. And apparently
that person received no warning that they could remember (even though,
I would have expected, the RAID BIOS should have complained on every
reboot, that something wasn't right - the status should have indicated
degradation for those three months).

In principle, what I'd want to see in a RAID1 design, is the ability to
check that the two disks are exact mirrors (offline check, like in the
BIOS, before the system boots). I realize, that commanding
the array to do a rebuild, guarantees that the disks are identical. But
it also runs the risk, of copying a "stale" image (like the three month
old example above) to the second disk.

1) Yes, RAID1 is an effective option. It is simple to understand, unlike
facing a broken RAID0+1 or RAID10.
2) The Southbridge RAID should work fine. Performance is good, as there
is a good connection bus-wise, to the rest of the system.
3) A RAID1 has the opportunity to accept read data from the first of
the two disks that are ready. In terms of raw bandwidth, there are now
some drives, which offer slightly more bandwidth than the Raptor. Where
the Raptor would excel, is in seek time. So on random access, the Raptor
might still be faster (bootup might still be faster on the Raptor).
4) You can place the boot volume on the RAID1. The RAID BIOS module in the
BIOS flash code, takes care of reading from the RAID, during bootup.
So that isn't a problem.

What is a problem, is getting a RAID driver onto the thing. If you ever
wanted to use RAID for booting, you'd enable RAID in the BIOS, connect
one disk, do F6 and install a RAID driver, even though there was only
one disk present. The Intel software supports migration, so you can go
from a single disk, to a RAID1 or a RAID0 or other form of RAID.

To take an OS install, in which no RAID driver was installed, and
move it to a RAID array, needs to get the driver installed somehow.
If you enable RAID, you cannot boot the existing disk. If you leave
the Southbridge in non-RAID mode, you cannot install a RAID driver.
So that is one of the challenges you'd face, if trying to put the
boot volume on the RAID. You need to be "RAID ready" from day one.

http://download.intel.com/support/ch...startguide.pdf

Paul

In article <fs6qsm$fs2$>, says...
> 1) Yes, RAID1 is an effective option. It is simple to understand, unlike
> facing a broken RAID0+1 or RAID10.
> 2) The Southbridge RAID should work fine. Performance is good, as there
> is a good connection bus-wise, to the rest of the system.
> 3) A RAID1 has the opportunity to accept read data from the first of
> the two disks that are ready. In terms of raw bandwidth, there are now
> some drives, which offer slightly more bandwidth than the Raptor. Where
> the Raptor would excel, is in seek time. So on random access, the Raptor
> might still be faster (bootup might still be faster on the Raptor).
> 4) You can place the boot volume on the RAID1. The RAID BIOS module in the
> BIOS flash code, takes care of reading from the RAID, during bootup.
> So that isn't a problem.
>
> What is a problem, is getting a RAID driver onto the thing. If you ever
> wanted to use RAID for booting, you'd enable RAID in the BIOS, connect
> one disk, do F6 and install a RAID driver, even though there was only
> one disk present. The Intel software supports migration, so you can go
> from a single disk, to a RAID1 or a RAID0 or other form of RAID.
>
> To take an OS install, in which no RAID driver was installed, and
> move it to a RAID array, needs to get the driver installed somehow.
> If you enable RAID, you cannot boot the existing disk. If you leave
> the Southbridge in non-RAID mode, you cannot install a RAID driver.
> So that is one of the challenges you'd face, if trying to put the
> boot volume on the RAID. You need to be "RAID ready" from day one.
>
> http://download.intel.com/support/ch...startguide.pdf
>
What a helpful post...much appreciated.

I think if I do go for raid I'll be using two new disks. Thus getting
the raid driver onto the boot disk won't be an issue. Raid 10 sounds
ideal, but since I'm new to this I think I'll keep my life simple and
just go for mirrored.

One addtl question I have which a read of the asus mobo manual does not
reveal is, at the stage that I key in the volume capacity...is that in
place of creating partions in windows? If so, and I ultimately want
three partitions (C,D,E) do I create all three separately there in the
Ctrl-I utility?

nano wrote:

> What a helpful post...much appreciated.
>
> I think if I do go for raid I'll be using two new disks. Thus getting
> the raid driver onto the boot disk won't be an issue. Raid 10 sounds
> ideal, but since I'm new to this I think I'll keep my life simple and
> just go for mirrored.
>
> One addtl question I have which a read of the asus mobo manual does not
> reveal is, at the stage that I key in the volume capacity...is that in
> place of creating partions in windows? If so, and I ultimately want
> three partitions (C,D,E) do I create all three separately there in the
> Ctrl-I utility?

Matrix RAID, makes it possible to have two logical arrays, present
on the same pair of disks. For example, say I owned a couple 120GB disks.
With Matrix RAID, I can do the following with two disks. This would involve
keying in the values, so that the appropriate portions are reserved for
each section.

Disk0 Disk1
43GB <---> 43GB RAID0 (86GB total - 2x bandwidth - no redundancy)
77GB <---> 77GB RAID1 (77GB total - a redundant configuration)

In Disk Management, you'd see two logical devices, and each could be
partitioned into multiple partitions. For example, I could define E:
and F: on the 86GB logical device. And C: and D: on the 77GB logical device.
You would set the size of C:,D:,E:, and F: in Disk Management.

What is messy about Matrix RAID, is what happens when a disk fails.
If Disk0 fails above, the RAID0 is cooked, so I lose E: and F:.
The RAID1 (reliable redundant configuration) continues to operate.
The above would be fine, if the RAID0 was my Photoshop scratch disk,
and all important files were kept on the RAID1.

If you wanted to keep it simple, and make a RAID0 of the entire space,
then leave the keyed in value at the maximum allowed. Using the 120GB
disks as an example, the result would look like this. Only one
logical device would show up in Disk Management.

Disk0 Disk1
120GB <---> 120GB RAID1 (120GB total - a redundant configuration)

HTH,
Paul

In article <fs78eq$nv1$>, says...
>
> Matrix RAID, makes it possible to have two logical arrays, present
> on the same pair of disks. For example, say I owned a couple 120GB disks.
> With Matrix RAID, I can do the following with two disks. This would involve
> keying in the values, so that the appropriate portions are reserved for
> each section.
>
> Disk0 Disk1
> 43GB <---> 43GB RAID0 (86GB total - 2x bandwidth - no redundancy)
> 77GB <---> 77GB RAID1 (77GB total - a redundant configuration)
>
> In Disk Management, you'd see two logical devices, and each could be
> partitioned into multiple partitions. For example, I could define E:
> and F: on the 86GB logical device. And C: and D: on the 77GB logical device.
> You would set the size of C:,D:,E:, and F: in Disk Management.
>
> What is messy about Matrix RAID, is what happens when a disk fails.
> If Disk0 fails above, the RAID0 is cooked, so I lose E: and F:.
> The RAID1 (reliable redundant configuration) continues to operate.
> The above would be fine, if the RAID0 was my Photoshop scratch disk,
> and all important files were kept on the RAID1.
>
> If you wanted to keep it simple, and make a RAID0 of the entire space,
> then leave the keyed in value at the maximum allowed. Using the 120GB
> disks as an example, the result would look like this. Only one
> logical device would show up in Disk Management.
>
> Disk0 Disk1
> 120GB <---> 120GB RAID1 (120GB total - a redundant configuration)
>
> HTH,
> Paul

Yes very helpful. One addtl question; you mentioned that some 7200 rpm
sata disks were close to raptor performance, can you point me at the
brand/model? I was thinking of seagate barracudas since I've had succes
with those in the past, but would consider alternatives.

nano wrote:

>
> Yes very helpful. One addtl question; you mentioned that some 7200 rpm
> sata disks were close to raptor performance, can you point me at the
> brand/model? I was thinking of seagate barracudas since I've had succes
> with those in the past, but would consider alternatives.

The list here, has SCSI and SATA mixed together. There are a few old IDE
at the bottom of the list, so presumably they don't test newer ones with
IDE interfaces.

http://www.storagereview.com/Testbed4Compare.sr

WD Cavier SE16 WD7500AAKS 97.0MB/sec max sustained read.
A Raptor 150GB is listed at 88.3MB/sec.

Sustained transfer isn't everything, and would be most beneficial
if dealing with large files or while sector by sector cloning.
The WD7500AAKS has average random access of 13.7msec, with the
Raptor at 7.7msec. For doing builds, reading lots of small
header files and the like, you'd want the Raptor. If the
intended applications are mainly random access of smaller files,
then optimizing for sustained transfer is silly. But if the
applications had linear access, like reading 300MB Photoshop files
or something, then the Cavier would be a slight win.

There are customer reviews for WD7500AAKS here, with plenty of DOA
and premature failures. And reports of running hot, which tells you,
like any large drives, to use good cooling. (The air intake on my
computer case, is right in front of the drive bay.)

http://www.newegg.com/Product/Produc...82E16822136131

Paul