WD1200JB/8MBcache + other disks

  • Thread starter Thread starter Stefek Burczymucha
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Stefek Burczymucha

Hi everyone.
I'm a happy owner of three disks now,

1. WDC WD1200JB, 8MB cache, 7200rpm, ATA 100
2. IBM DTLA 46GB, 2MB cache, 7200rpm, ATA 100
3. Seagate Barracuda 40GB, 2MB cache, 7200rpm, ATA 100

My questions are:
1. What RAID controller would you recommend to use, and
2. Does the fact that disks 2 and 3 are only 2MB cache influence in any way
the performance of disk 1? If so, how?
 
Hi everyone.
I'm a happy owner of three disks now,

1. WDC WD1200JB, 8MB cache, 7200rpm, ATA 100
2. IBM DTLA 46GB, 2MB cache, 7200rpm, ATA 100
3. Seagate Barracuda 40GB, 2MB cache, 7200rpm, ATA 100

My questions are:
1. What RAID controller would you recommend to use, and
2. Does the fact that disks 2 and 3 are only 2MB cache influence in any way
the performance of disk 1? If so, how?
Click to expand...

Which RAID mode do you want to use ? One that makes up a hotbackup as you
go or the mode that puts some data on one drive and then the other for
faster disk access ?

To really work like it should you need to have matching disks. If not then
you are limiated by the smallest one on the aray.
 
Fri, 23 Jan 2004 11:34:10 -0500, na alt.comp.hardware, Ralph Mowery
napisa³(a):
Which RAID mode do you want to use ? One that makes up a hotbackup as you
go or the mode that puts some data on one drive and then the other for
faster disk access ?
Click to expand...

I think I need more explanation on it... I don't know what to choose.
To really work like it should you need to have matching disks. If not then
you are limiated by the smallest one on the aray.
Click to expand...

I think you mean the performance will be downgraded only if the disks move
files from one to another but I guess that does not affect other
activities, right?
 
1. What RAID controller would you recommend to use, and
I think I need more explanation on it... I don't know what to choose.


I think you mean the performance will be downgraded only if the disks move
files from one to another but I guess that does not affect other
activities, right?
Click to expand...

Are you sure you are even talking about RAID. If so you need to get on
Google and look up some information about the various ways RAID can be used.

If you just want to install the 3 drives in a computer and use them for
storage you are not really talking about using RAID. YOu can put 2 IDE
devices on each controler. Most motherboards will have 2 connectors that
will handle 2 devices each. That means you can use 2 hard drives one one
connector and the third hard drive and one CD or a CD-RW on the other
connector.

There will not be any speed interaction in the hard drives you have.
 
Fri, 23 Jan 2004 16:40:23 -0500, na alt.comp.hardware, Ralph Mowery
napisa³(a):
Are you sure you are even talking about RAID. If so you need to get on
Google and look up some information about the various ways RAID can be used.

If you just want to install the 3 drives in a computer and use them for
storage you are not really talking about using RAID. YOu can put 2 IDE
devices on each controler. Most motherboards will have 2 connectors that
will handle 2 devices each. That means you can use 2 hard drives one one
connector and the third hard drive and one CD or a CD-RW on the other
connector.

There will not be any speed interaction in the hard drives you have.
Click to expand...

I know I'm not much of a computer nerd but I'm not that dumb ;) I'm aware
of the fact that most motherboards are equipped with 2 HDD connectors and
so is mine. It's an MSI KT4V - it's not a problem with the board. I have 2
HDDs connected to one socket and a CD burner and a DVD drive to another. So
as you can see I have to connect another disk. I figured I need a RAID
controller. Am I wrong?
 
Fri, 23 Jan 2004 16:40:23 -0500, na alt.comp.hardware, Ralph Mowery
napisa³(a):


I know I'm not much of a computer nerd but I'm not that dumb ;) I'm aware
of the fact that most motherboards are equipped with 2 HDD connectors and
so is mine. It's an MSI KT4V - it's not a problem with the board. I have 2
HDDs connected to one socket and a CD burner and a DVD drive to another. So
as you can see I have to connect another disk. I figured I need a RAID
controller. Am I wrong?
Click to expand...

You need an add on controller. It doesn't have to be RAID. Many RAID
controllers will also function as just an add on controller as well, but
why pay extra for RAID if you aren't going to use it.

JT
 
Fri, 23 Jan 2004 22:34:04 GMT, na alt.comp.hardware, JT napisaù(a):
You need an add on controller. It doesn't have to be RAID. Many RAID
controllers will also function as just an add on controller as well, but
why pay extra for RAID if you aren't going to use it.
Click to expand...
OK but I always want to be sure that I won't regret my choice later so what
is this RAID controller? What would I be losing if I dont buy it?
 
Hmmm ... To use RAID you have to use harddrives in the array of IDENTICAL
size. You can't use mismatched sizes in a RAID array.
 
Fri, 23 Jan 2004 22:34:04 GMT, na alt.comp.hardware, JT napisaù(a):
Click to expand...
OK but I always want to be sure that I won't regret my choice later so what
is this RAID controller? What would I be losing if I dont buy it?
Click to expand...

RAID lets you set up an array of disks to act like a single disk.
Sometimes for increased speed, sometimes for increased reliability. A
controller does this through hardware/firmware. You need to research RAID
to see if it is something you might want/need. As has been noted
previously, it requires pretty much identical disks to function properly.

JT
 
DaveW said:
Hmmm ... To use RAID you have to use harddrives in the array of IDENTICAL
size. You can't use mismatched sizes in a RAID array.
Click to expand...
This is not always the case, but the capacity of the smallest disk has to be
used and any larger disk will have wasted space that can not be used.
Maybe not that bad for a 40 and 46 GB drive as you only give up 6 GB, but
you would not want to use the 40 and 120 GB drive as you would loose 80 gb
of space.
 
OK but I always want to be sure that I won't regret my choice later so what
is this RAID controller? What would I be losing if I dont buy it?
Click to expand...

Let's look at the facts. You have a motherboard that lacks
southbridge-integrated RAID, so any add-on card will use the PCI bus
and be of lower performance *overall* than a southbridge-integrated
controller. Also you have three drives of different specs.

The WD 120GB, is a lot faster than the other two... that should be
your OS drive, unless you have an atypical useage that would make OS
performance a secondary concern compared to specific applications.
For most people the most benefit would be having that WD drive as the
primary OS drive.

Your other two drives, while not exactly the same size, are close
enough that it's not much (6GB) of a loss to do a RAID with them, _IF_
that's what you want or need to do. It is NOT necessary to use two
drives of identical specs, there is NO BENEFIT to doing that, except
that if one drive is larger than the other, you loose the excess
capacity of that one larger drive, which in this case would be 6GB of
space.

A RAID 1 will mirror one drive to the other, so you have 40GB of space
essentially used-up to make the mirror of the other drive. It will
have slower write speed but a little faster read speed than same
drive(s) in non-RAID. Or, RAID 0 those two, probably better sustained
write and read, latency, but bottlenecked and added latency from PCI
bus. You'd likely be better off just using the WD 120GB drive alone
for whatever purpose requires the most performance.

What I'd do in your situation is to buy (either) a RAID PCI card OR a
non-RAID IDE card, but either way, one that supports ATAPI devices
(the optical drives). IIRC, some RAID cards do support this, (like
SIIG chipset cards) but others don't, like Promise chipset. I forget
whether Highpoint RAID cards do or not. Then I'd put the optical
drives on the RAID/IDE PCI controller card and run the HDDs from the
faster motherboard controller, which removes the PCI bus from the
access and so is usually faster, also leaving more PCI throughtput for
other PCI devices. Of course this means none of the HDDs would be in
a RAID array, but it's not so clear that you'd benefit from a RAID 0
array, and it seems not many people are wanting RAID1 these days.
RAID1 is a good strategy for 24/7 servers but for a PC home-user
running windows there might be more benefit to leaving the 2nd HDD
(that would be in the RAID1) disconnected, only connecting it to make
backups, then protecting it from (anything, whether it be viri or
power surges or user-error) by disconnection except when backups or
restores are underway. On the other hand, if you don't plan on using
any of the HDDs for backup purposes, there are many uses of HDD that
don't require peak throughput, only a minmal level of sustained
thoughpt easily met by those drives, like MP3s and video, or
compressed archives.
 
This is not always the case, but the capacity of the smallest disk has to be
used and any larger disk will have wasted space that can not be used.
Maybe not that bad for a 40 and 46 GB drive as you only give up 6 GB, but
you would not want to use the 40 and 120 GB drive as you would loose 80 gb
of space.
Click to expand...

It's never the case that they have to be identical, AFAIK. Does
anyone have a concrete example of a card that can't use different
drives?
 
Let's look at the facts. You have a motherboard that lacks
southbridge-integrated RAID, so any add-on card will use the PCI bus
and be of lower performance *overall* than a southbridge-integrated
controller. Also you have three drives of different specs.

The WD 120GB, is a lot faster than the other two... that should be
your OS drive, unless you have an atypical useage that would make OS
performance a secondary concern compared to specific applications.
For most people the most benefit would be having that WD drive as the
primary OS drive.

Your other two drives, while not exactly the same size, are close
enough that it's not much (6GB) of a loss to do a RAID with them, _IF_
that's what you want or need to do. It is NOT necessary to use two
drives of identical specs, there is NO BENEFIT to doing that, except
that if one drive is larger than the other, you loose the excess
capacity of that one larger drive, which in this case would be 6GB of
space.

A RAID 1 will mirror one drive to the other, so you have 40GB of space
essentially used-up to make the mirror of the other drive. It will
have slower write speed but a little faster read speed than same
drive(s) in non-RAID. Or, RAID 0 those two, probably better sustained
write and read, latency, but bottlenecked and added latency from PCI
bus. You'd likely be better off just using the WD 120GB drive alone
for whatever purpose requires the most performance.

What I'd do in your situation is to buy (either) a RAID PCI card OR a
non-RAID IDE card, but either way, one that supports ATAPI devices
(the optical drives). IIRC, some RAID cards do support this, (like
SIIG chipset cards) but others don't, like Promise chipset. I forget
whether Highpoint RAID cards do or not. Then I'd put the optical
drives on the RAID/IDE PCI controller card and run the HDDs from the
faster motherboard controller, which removes the PCI bus from the
access and so is usually faster, also leaving more PCI throughtput for
other PCI devices. Of course this means none of the HDDs would be in
a RAID array, but it's not so clear that you'd benefit from a RAID 0
array, and it seems not many people are wanting RAID1 these days.
RAID1 is a good strategy for 24/7 servers but for a PC home-user
running windows there might be more benefit to leaving the 2nd HDD
(that would be in the RAID1) disconnected, only connecting it to make
backups, then protecting it from (anything, whether it be viri or
power surges or user-error) by disconnection except when backups or
restores are underway. On the other hand, if you don't plan on using
any of the HDDs for backup purposes, there are many uses of HDD that
don't require peak throughput, only a minmal level of sustained
thoughpt easily met by those drives, like MP3s and video, or
compressed archives.
Click to expand...

Thanks Kony - that's all I needed to know ;)
 
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