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Old 02-09-2010, 09:17 PM
"J. Roeleveld"
 
Default 1-Terabyte drives - 4K sector sizes? -> bar performance so far

On Tuesday 09 February 2010 22:13:39 Frank Steinmetzger wrote:
<snipped>
> When I use parted on the drives, it says (both the old external and my 2
> months old internal):
> Sector size (logical/physical): 512B/512B
> So no speedup for me then. :-/
>

That doesn't mean a thing, I'm afraid.
I have the 4KB drives (product-code and behaviour match) and parted also
claims my drives have a 512B logical/physical sector size.
 
Old 02-09-2010, 10:22 PM
Iain Buchanan
 
Default 1-Terabyte drives - 4K sector sizes? -> bar performance so far

On Tue, 2010-02-09 at 08:47 +0100, J. Roeleveld wrote:

> I now only need to figure out the best way to configure LVM over this to get
> the best performance from it. Does anyone know of a decent way of figuring
> this out?
> I got 6 disks in Raid-5.

why LVM? Planning on changing partition size later? LVM is good for
(but not limited to) non-raid setups where you want one partition over a
number of disks.

If you have RAID 5 however, don't you just get one large disk out of it?
In which case you could just create x partitions. You can always use
parted to resize / move them later.

IMHO recovery from tiny boot disks is easier without LVM too.

--
Iain Buchanan <iaindb at netspace dot net dot au>

Failure is not an option -- it comes bundled with Windows.
 
Old 02-09-2010, 10:37 PM
Iain Buchanan
 
Default 1-Terabyte drives - 4K sector sizes? -> bar performance so far

On Tue, 2010-02-09 at 13:34 +0000, Neil Bothwick wrote:
> On Tue, 9 Feb 2010 12:46:40 +0000, Stroller wrote:
>
> > > With the RAID, you could fail one disk, repartition, re-add it,
> > > rinse and
> > > repeat. But that doesn't take care of the time issue.
> >
> > Aren't you thinking of LVM, or something?
>
> No. The very nature of RAID is redundancy, so you could remove one disk
> from the array to modify its setup then replace it.

so long as you didn't have any non-detectable disk errors before
removing the disk, or any drive failure while one of the drives were
removed. And the deterioration in performance while each disk was
removed in turn might take more time than its worth. Of course RAID 1
wouldn't suffer from this (with >2 disks)...
--
Iain Buchanan <iaindb at netspace dot net dot au>

Keep on keepin' on.
 
Old 02-09-2010, 10:52 PM
Iain Buchanan
 
Default 1-Terabyte drives - 4K sector sizes? -> bar performance so far

On Tue, 2010-02-09 at 20:37 +0100, J. Roeleveld wrote:

> Don't get me started on those
> The reason I use Linux Software Raid is because:
> 1) I can't afford hardware raid adapters
> 2) It's generally faster then hardware fakeraid

I'm starting to stray OT here, but I'm considering a second-hand Adaptec
2420SA - this is real hardware raid right?

If I'm buying drives in the 1Tb size - does this 4k issue affect
hardware RAID and how do you get around it? (Never set up a HW RAID
card before)

thanks,
--
Iain Buchanan <iaindb at netspace dot net dot au>

You know you're using the computer too much when:
you count from zero all the time.
-- Stormy Eyes
 
Old 02-09-2010, 11:11 PM
Peter Humphrey
 
Default 1-Terabyte drives - 4K sector sizes? -> bar performance so far

On Tuesday 09 February 2010 18:03:39 Neil Walker wrote:

> Be lucky,
>
> Neil

How would I go about doing that?

--
Rgds
Peter.
 
Old 02-09-2010, 11:31 PM
Iain Buchanan
 
Default 1-Terabyte drives - 4K sector sizes? -> bar performance so far

On Tue, 2010-02-09 at 14:54 -0800, Mark Knecht wrote:
> On Tue, Feb 9, 2010 at 1:13 PM, Frank Steinmetzger <Warp_7@gmx.de> wrote:


> > When I use parted on the drives, it says (both the old external and my 2
> > months old internal):
> > Sector size (logical/physical): 512B/512B
> > So no speedup for me then. :-/

so does mine

> Frank,
> As best I can tell so far none of the Linux tools will tell you
> that the sectors are 4K. I had to go to the WD web site and find the
> actual drive specs to discover that was true.

however if you use dmesg:
$ dmesg | grep ata
ata1: SATA max UDMA/133 irq_stat 0x00400040, connection status changed
irq 17
ata2: DUMMY
ata3: SATA max UDMA/133 abar m2048@0xf6ffb800 port 0xf6ffba00 irq 17
ioatdma: Intel(R) QuickData Technology Driver 4.00
ata3: SATA link down (SStatus 0 SControl 300)
ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata1.00: ATA-7: ST9160823ASG, 3.ADD, max UDMA/133
ata1.00: 312581808 sectors, multi 8: LBA48 NCQ (depth 31/32)
...

you can look up your drive model number (in my case ST9160823ASG) and
find out the details. (That's a Seagate Momentus 160Gb with actual 512
byte sectors).

saves having to open up your laptop / pc if you didn't order the drive
separately or you've forgotten.
--
Iain Buchanan <iaindb at netspace dot net dot au>

polygon:
Dead parrot.
 
Old 02-10-2010, 12:16 AM
Stroller
 
Default 1-Terabyte drives - 4K sector sizes? -> bar performance so far

On 9 Feb 2010, at 23:52, Iain Buchanan wrote:

...
I'm starting to stray OT here, but I'm considering a second-hand
Adaptec

2420SA - this is real hardware raid right?


Looks like it. Looks pretty nice, too.

The affordable PCI / PCI-X 3wares don't do RAID6 - you have to go PCIe
for that, I think - and that "snapshot backup" feature looks cute.



If I'm buying drives in the 1Tb size - does this 4k issue affect
hardware RAID and how do you get around it? (Never set up a HW RAID
card before)


Posted elsewhere - I think it'll be just the same.

Stroller.
 
Old 02-10-2010, 12:28 AM
Stroller
 
Default 1-Terabyte drives - 4K sector sizes? -> bar performance so far

On 9 Feb 2010, at 19:37, J. Roeleveld wrote:

...
Don't get me started on those
The reason I use Linux Software Raid is because:
1) I can't afford hardware raid adapters
2) It's generally faster then hardware fakeraid


I'd rather have slow hardware RAID than fast software RAID. I'm not
being a snob, it just suits my purposes better.


If speed isn't an issue then secondhand prices of SATA RAID
controllers (PCI & PCI-X form-factor) are starting to become really
cheap. Obviously new cards are all PCI-e - industry has long moved to
that, and enthusiasts are following.


I would be far less invested in hardware RAID if I could find regular
SATA controllers which boasted hot-swap. I've read reports of people
hot-swapping SATA drives "just fine" on their cheap controllers but
last time I checked there were no manufacturers who supported this as
a feature.


Stroller.
 
Old 02-10-2010, 05:31 AM
Volker Armin Hemmann
 
Default 1-Terabyte drives - 4K sector sizes? -> bar performance so far

On Mittwoch 10 Februar 2010, Iain Buchanan wrote:
> On Tue, 2010-02-09 at 13:34 +0000, Neil Bothwick wrote:
> > On Tue, 9 Feb 2010 12:46:40 +0000, Stroller wrote:
> > > > With the RAID, you could fail one disk, repartition, re-add it,
> > > > rinse and
> > > > repeat. But that doesn't take care of the time issue.
> > >
> > > Aren't you thinking of LVM, or something?
> >
> > No. The very nature of RAID is redundancy, so you could remove one disk
> > from the array to modify its setup then replace it.
>
> so long as you didn't have any non-detectable disk errors before
> removing the disk, or any drive failure while one of the drives were
> removed. And the deterioration in performance while each disk was
> removed in turn might take more time than its worth. Of course RAID 1
> wouldn't suffer from this (with >2 disks)...

Raid 6. Two disks can go down.
 
Old 02-10-2010, 05:48 AM
Neil Walker
 
Default 1-Terabyte drives - 4K sector sizes? -> bar performance so far

Peter Humphrey wrote:
> On Tuesday 09 February 2010 18:03:39 Neil Walker wrote:
>
>
>> Be lucky,
>>
>> Neil
>>
>
> How would I go about doing that?
>

Well, you need a rabbit's foot, a four leaf clover, a horseshoe
(remember to keep the open end uppermost), a black cat, ........



Be lucky,

Neil
 

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