IO thruput via SATA ports

[Kyp]

I'm new to using SATA and would like to know the recommended way to
add SATA drives to maximize IO thruput.

My mother board, Intel DQ965GF has 6 SATA ports. The specs indicate
that I can get 3Gb/sec for each port (theoretically).

I would like to add about 1TB of storage. Is it better to have 3
smaller drives (~320GB) or 1 1TB drive. I suspect that more drive
spindles is better. But for IDE, with the master/slave, with the 2
devices per channel.

Also, the motherboard supports SATA: IDE/Raid. I think I'm going with
IDE, any performance penalty?

Anyone have any recommendations? Anything I'm missing/overlooking?

thanx, mark

 

[Arno]

I'm new to using SATA and would like to know the recommended way to
add SATA drives to maximize IO thruput.

My mother board, Intel DQ965GF has 6 SATA ports. The specs indicate
that I can get 3Gb/sec for each port (theoretically).

I would like to add about 1TB of storage. Is it better to have 3
smaller drives (~320GB) or 1 1TB drive. I suspect that more drive
spindles is better. But for IDE, with the master/slave, with the 2
devices per channel.

Also, the motherboard supports SATA: IDE/Raid. I think I'm going with
IDE, any performance penalty?

Anyone have any recommendations? Anything I'm missing/overlooking?

thanx, mark

What do you want to achive? Throughput is not very relevant,
except in specific situations. Also using several drives
you would either have to RAID them or partition your data.

Arno

 

[Rod Speed]

Kyp wrote

I'm new to using SATA and would like to know the recommended
way to add SATA drives to maximize IO thruput.

My mother board, Intel DQ965GF has 6 SATA ports. The specs
indicate that I can get 3Gb/sec for each port (theoretically).

I would like to add about 1TB of storage. Is it better
to have 3 smaller drives (~320GB) or 1 1TB drive.

You cant do it as simplistically as that. Some of the 1TB drives
have rather better thruput than the 320GB drives, the sectors
move under the heads rather more quickly and thats what
determines thruput with the movement of substantial files.

Corse you should be organising things so you dont move
substantial files much except for backup and with backup
the IO thruput usually doesnt matter much because most
do their backup when they arent using the PC anyway.

I suspect that more drive spindles is better.

Its rather more complicated than that, particularly when
with mulitiple spindles you are much more likely to be moving
substantial files around because they are on the wrong drive etc.

But for IDE, with the master/slave, with the 2 devices per channel.

All drives are one per channel with sata.

Also, the motherboard supports SATA: IDE/Raid.
I think I'm going with IDE, any performance penalty?

Normally not.

Anyone have any recommendations?

I prefer one physical drive and one partition per physical drive now.

Anything I'm missing/overlooking?

The partitioning.

 

[Yousuf Khan]

I'm new to using SATA and would like to know the recommended way to
add SATA drives to maximize IO thruput.

My mother board, Intel DQ965GF has 6 SATA ports. The specs indicate
that I can get 3Gb/sec for each port (theoretically).

In general, the access method does not make a huge difference to the
performance of SATA drives. SATA drives can be accessed in one of three
modes: (1) IDE emulation, (2) AHCI native mode, or (3) RAID mode. The
3rd mode is a bit of a fake mode, it's really using the AHCI mode and
hiding the internal configuration of disks from the operating system.

The AHCI mode adds such capabilities as NCQ (Native Command Queuing)
which supposedly helps in organizing disk access patterns better. Also
it allows you to use eSATA external disks and make them removable
devices. Other than that, there's not much of advantage over the IDE
emulation mode; in this mode, everything appears as UDMA6.

I would like to add about 1TB of storage. Is it better to have 3
smaller drives (~320GB) or 1 1TB drive. I suspect that more drive
spindles is better. But for IDE, with the master/slave, with the 2
devices per channel.

I think throughput seems to be limited by access time on these drives.
I've found that the disk queue length gets attacked pretty heavily while
under Windows. I haven't been able to determine what inside Windows is
attacking the disk queue that much, but it takes a lot of throughput out
of the system, if it's busy constantly trying to service numerous small
requests.

Yousuf Khan

 

[Rod Speed]

Yousuf Khan wrote

Kyp wrote

In general, the access method does not make a huge difference to the
performance of SATA drives. SATA drives can be accessed in one of
three modes: (1) IDE emulation, (2) AHCI native mode, or (3) RAID
mode. The 3rd mode is a bit of a fake mode, it's really using the
AHCI mode and hiding the internal configuration of disks from the
operating system.

The AHCI mode adds such capabilities as NCQ (Native Command Queuing)
which supposedly helps in organizing disk access patterns better. Also
it allows you to use eSATA external disks and make them removable
devices. Other than that, there's not much of advantage over the IDE
emulation mode; in this mode, everything appears as UDMA6.

I think throughput seems to be limited by access time on these drives.

Nope, not with moving substantial files around.

I've found that the disk queue length gets attacked pretty heavily while under Windows.

Thats not right either. Few systems have their hard drive led on most of the time.

I haven't been able to determine what inside Windows is attacking the disk queue that much, but it takes a lot of
throughput out of the system, if it's busy constantly trying to
service numerous small requests.

Thats just plain wrong.

 

[mscotgrove]

Add an external eSATA drive--up to 3TB, but can be 1TB and
up. That way, it can be removed when needed. Could go USB3
also, depends what you are backing up and how often.

I have a 4-drive eSATA box connected to my computer and have
few problems. There are 4x1TB HDDs running JBOD (4
independent drives each with its own drive letter). Been
using it for 2+years and do recommend it to others. The mfr
now offers the same box with eSATA and USB3.- Hide quoted text -

- Show quoted text -

I think in most cases the operating system and file system is the
slowest part of the equation. It does depend to a very large extent
on number and size of files being copied. Linux can be fast, Windows,
FAT32 is slow.

My feeling is that the easiest way to slow the drive down is to
'thrash' it by copying files within the same drive. These causes the
heads to be moving all of the time.

Do do file copies, three smaller drives could be better, as long as a
copy was always between different drives.

Adequate memory is also important.

Michael
www.cnwrecovery.com

 

[Rod Speed]

Gerald Abrahamson wrote

Add an external eSATA drive--up to 3TB, but can be 1TB and
up. That way, it can be removed when needed. Could go USB3
also, depends what you are backing up and how often.

I have a 4-drive eSATA box connected to my computer and
have few problems. There are 4x1TB HDDs running JBOD
(4 independent drives each with its own drive letter). Been
using it for 2+years and do recommend it to others. The
mfr now offers the same box with eSATA and USB3.

You didnt mention the manufacturer's name or model.

Trouble with those is that they cost as much as one of the drives, often more.

 

[Rod Speed]

Gerald Abrahamson wrote

Here you go. I have the same box with eSATA. Big fan
in back to keep air moving. It was about $200 then,

Still is now.

add $20 for the dual-port PCIe/eSATA card. Not cheap,

In fact three times as much as one of the drives inside it if you fill it with 2TB drives.

So its getting on for doubling the cost of all the drives inside it cost.

 

[Rod Speed]

Gerald Abrahamson wrote

You can't RAID drives (especially hot swap a drive) that are on individual cables.

I dont want to RAID them.

So, there is value in it *if* you plan ahead.

I never said it had no value, just that come close to doubling the cost of the drives.

Plus, the individual drives in a RAID box can be run JBOD--
which means they can be upgraded individually as needed.

So can the other obvious much cheaper alternative, drive docking stations.

Plus, the usual warranty on an external drive is 1 year
vs 3 years for drives bought and installed in a RAID box.

Just as true of the other obvious much cheaper alternative, drive docking stations.

Then there is just one power cable and one data cable for 4 drives vs 4 of each for individual boxes.

But not for drive docking stations.

 

[Yousuf Khan]

You can't RAID drives (especially hot swap a drive) that are
on individual cables. So, there is value in it *if* you plan
ahead. Plus, the individual drives in a RAID box can be run
JBOD--which means they can be upgraded individually as
needed. Plus, the usual warranty on an external drive is 1
year vs 3 years for drives bought and installed in a RAID
box. Then there is just one power cable and one data cable
for 4 drives vs 4 of each for individual boxes.

Having a true hardware RAID that doesn't require any OS drivers does
have some major value. However, there maybe some interface limitations
that'll scuttle the deal. Do you know if the combined internal capacity
can be over 2TB?

Yousuf Khan

 

[Rod Speed]

Yousuf Khan wrote

Gerald Abrahamson wrote

Having a true hardware RAID that doesn't require any OS drivers does have some major value.

And has some massive downsides too, particularly
if you cant afford to duplicate that raid hardware.

 

[Yousuf Khan]

Read the specs on the enclosure--disk spanning is not RAID.
It may be able to do it, but can't say one way or the other.

Yes, but it's similar enough. RAID 0 (striping) is a more sophisticated
version of spanning.

Yousuf Khan

 

[Yousuf Khan]

Read the specs on the enclosure--disk spanning is not RAID.
It may be able to do it, but can't say one way or the other.

Yes, but it's similar enough. RAID 0 (striping) is a more sophisticated
version of spanning.

In my case, the limitation was not due to any technical differences
between spanning and striping, it simply due to a limitation in the USB
drivers that don't recognize drives greater than 2 TB per device.

Yousuf Khan

 

[Bob Willard]

Yes, but it's similar enough. RAID 0 (striping) is a more sophisticated
version of spanning.

And a car is a more sophisticated version of a donkey cart.

The purpose of striping is higher performance on single-stream R/W, and
more capacity. The purpose of spanning is simply more capacity; no
higher performance on single-stream R/W.

{Obviously, with multi-stream R/W from some workloads, any of striping,
spanning, or JBOD, should get higher performance than a single HD.}