Re: [zfs-discuss] "NearLine SAS"?

[Errol Neal]

On Tue, Jan 19, 2010 01:36  PM, "A. Krijgsman"  wrote:
> Yes, those i meant! (interposer cards, could get on that name!)
> The Dell's and HP's would al work in any enviroment?
> 
> It's just plain converting between industry standards right?
> 
> Or do people have a better solution to share a single SSD from a JBOD 
> between
> two hosts?
> 
> Regards,
> Armand
> 

Perhaps I didn't read your post in it's entirety. If your goal is to share a 
single drive between two jbod systems, an interposer card won't help.

There was some talk on the list about sharing SSDs over low latency networks. 
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Re: [zfs-discuss] "NearLine SAS"?

[Errol Neal]

On Tue, Jan 19, 2010 01:02  PM, "A. Krijgsman"  wrote:
> I was today reasearching this same phenomenon.
> The multipath is required for HA storage solutions with redundant i/o path 
> backplanes and redundant controllers.
> ( If a controller fails, the other one can still access the harddisk.)
> 
> I read about an LSI SAS-to-SATA bridge what can be attacched onto an 
> ordinary SATA
> drive to make it operate like a SAS drive (e.g. be able to multi path to 
> that drive.)
> Is there anyone on the list that can give some information about this?
> 
> I am google-ing my pants of to find some kind of shop selling these bridges.
> I want to build a redundant JBOD to share between two ZFS 
> hosts.(Active/Standby)
> 
> I already found the nearline SAS disks, but this will not fix the multipath 
> problem for SATA SSD disks.
> 
> Regards,
> Armand

I assume you mean these type of interposer cards?

e.g 
http://www.lsi.com/DistributionSystem/AssetDocument/SCG_LSISS9252_PB_082709.pdf

Based on my experiences, they generally go to VARs or OEMs e.g. Dell, HP. I do 
recall seeing some older gens on a 2950 that passed my way..
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Re: [zfs-discuss] "NearLine SAS"?

[A. Krijgsman]

I was today reasearching this same phenomenon.
The multipath is required for HA storage solutions with redundant i/o path 
backplanes and redundant controllers.

( If a controller fails, the other one can still access the harddisk.)

I read about an LSI SAS-to-SATA bridge what can be attacched onto an 
ordinary SATA
drive to make it operate like a SAS drive (e.g. be able to multi path to 
that drive.)

Is there anyone on the list that can give some information about this?

I am google-ing my pants of to find some kind of shop selling these bridges.
I want to build a redundant JBOD to share between two ZFS 
hosts.(Active/Standby)


I already found the nearline SAS disks, but this will not fix the multipath 
problem for SATA SSD disks.


Regards,
Armand



- Original Message - 
From: "Erik Trimble" 

To: "Tim Cook" 
Cc: "zfs-discuss" 
Sent: Tuesday, January 19, 2010 8:06 AM
Subject: Re: [zfs-discuss] "NearLine SAS"?



Tim Cook wrote:



On Tue, Jan 19, 2010 at 12:16 AM, Erik Trimble <mailto:erik.trim...@sun.com>> wrote:


A poster in another forum mentioned that Seagate (and Hitachi,
amongst others) is now selling something labeled as "NearLine SAS"
storage  (e.g. Seagate's NL35 series).

Is it me, or does this look like nothing more than their standard
7200-rpm enterprise drives with a SAS or FC interface instead of a
SATA one?

I can't see any real advantage of those over the existing
enterprise SATA drives (e.g. Seagate's Constellation ES series),
other than not needing a FC/SAS->SATA gateway in the external
drive enclosure.



Seagate claims the SAS versions of their drives actually see IOPS 
improvements:

http://www.seagate.com/www/en-us/products/servers/barracuda_es/barracuda_es.2

If the SAS version is dual ported like I would expect, that's also a 
MAJOR benefit.


--
--Tim
stupid question here:  I understand the advantages of dual-porting a drive 
with a FC interface, but for SAS, exactly what are the advantages other 
than being able to read and write simultaneously (obviously, only from the 
on-drive cache).
And yeah, these Seagates are dual-ported SAS. (according to the spec 
sheet)


Also, a 38% increase in IOPS without LESS drive cache seems unlikely.  Or, 
at least highly workload-dependent.
Check that, they're claiming 38% better IOPS/watt over the SATA version, 
which, given that the SAS one pulls 10% more watts, means in absolute 
terms 45% or so.   I'm really skeptical that only an interface change can 
do that.



--
Erik Trimble
Java System Support
Mailstop:  usca22-123
Phone:  x17195
Santa Clara, CA

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Re: [zfs-discuss] "NearLine SAS"?

[Tim Cook]

On Tue, Jan 19, 2010 at 4:17 AM, Andrew Gabriel wrote:

>
> Actually, this sounds like really good news for ZFS.
> ZFS (or rather, Solaris) can make good use of the multi-pathing capability,
> only previously available on high speed drives.
> Of course, ZFS can make use of any additional IOPs to be had, again only
> previously available on high speed drives.
> However, ZFS generally doesn't need high speed drives and does much better
> with hybrid storage pools.
>
> So these drives sound to me to have been designed specifically for ZFS!
> It's hard to imagine any other filesystem which can exploit them so
> completely.
>
>
>
You mean like WAFL?

-- 
--Tim
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Re: [zfs-discuss] "NearLine SAS"?

[Andrew Gabriel]

Edward Ned Harvey wrote:

A poster in another forum mentioned that Seagate (and Hitachi, amongst
others) is now selling something labeled as "NearLine SAS" storage
(e.g. Seagate's NL35 series).


Industry has moved again.  Better get used to it.

Nearline SAS is a replacement for SATA.  It's a lower cost drive than SAS,
with higher reliability than SATA.  I have begun seeing vendors that sell
only SAS and NearLine SAS.  (Some dell servers.)

SATA is not dead.  But this will certainly change things up a bit.


Actually, this sounds like really good news for ZFS.
ZFS (or rather, Solaris) can make good use of the multi-pathing 
capability, only previously available on high speed drives.
Of course, ZFS can make use of any additional IOPs to be had, again only 
previously available on high speed drives.
However, ZFS generally doesn't need high speed drives and does much 
better with hybrid storage pools.


So these drives sound to me to have been designed specifically for ZFS! 
It's hard to imagine any other filesystem which can exploit them so 
completely.


--
Andrew
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Re: [zfs-discuss] "NearLine SAS"?

[Edward Ned Harvey]

> A poster in another forum mentioned that Seagate (and Hitachi, amongst
> others) is now selling something labeled as "NearLine SAS" storage
> (e.g. Seagate's NL35 series).

Industry has moved again.  Better get used to it.

Nearline SAS is a replacement for SATA.  It's a lower cost drive than SAS,
with higher reliability than SATA.  I have begun seeing vendors that sell
only SAS and NearLine SAS.  (Some dell servers.)

SATA is not dead.  But this will certainly change things up a bit.

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Re: [zfs-discuss] "NearLine SAS"?

[Tim Cook]

On Tue, Jan 19, 2010 at 1:06 AM, Erik Trimble  wrote:

>  stupid question here:  I understand the advantages of dual-porting a drive
> with a FC interface, but for SAS, exactly what are the advantages other than
> being able to read and write simultaneously (obviously, only from the
> on-drive cache).
> And yeah, these Seagates are dual-ported SAS. (according to the spec sheet)
>

Path redundancy.  While it's fairly rare, paths to drives do go down.
Redundancy is a good thing :)


> Also, a 38% increase in IOPS without LESS drive cache seems unlikely.  Or,
> at least highly workload-dependent.
> Check that, they're claiming 38% better IOPS/watt over the SATA version,
> which, given that the SAS one pulls 10% more watts, means in absolute terms
> 45% or so.   I'm really skeptical that only an interface change can do that.
>
>
Without benchmarking myself, I can't really speak much to their claims.  I
WILL however say it's VERY unlikely they'd drop the cache on something
intended for the enterprise without being extremely confident its
performance would be the same or better.  It wouldn't surprise me at all to
hear the components they use for their SAS interfaces yield significantly
better performance.  Plus, if it's dual ported...  I wouldn't expect to see
38% consistently, but I would expect to see better performance across the
board.

-- 
--Tim
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Re: [zfs-discuss] "NearLine SAS"?

[Erik Trimble]

Tim Cook wrote:



On Tue, Jan 19, 2010 at 12:16 AM, Erik Trimble > wrote:


A poster in another forum mentioned that Seagate (and Hitachi,
amongst others) is now selling something labeled as "NearLine SAS"
storage  (e.g. Seagate's NL35 series).

Is it me, or does this look like nothing more than their standard
7200-rpm enterprise drives with a SAS or FC interface instead of a
SATA one?

I can't see any real advantage of those over the existing
enterprise SATA drives (e.g. Seagate's Constellation ES series),
other than not needing a FC/SAS->SATA gateway in the external
drive enclosure.



Seagate claims the SAS versions of their drives actually see IOPS 
improvements:

http://www.seagate.com/www/en-us/products/servers/barracuda_es/barracuda_es.2

If the SAS version is dual ported like I would expect, that's also a 
MAJOR benefit.


--
--Tim
stupid question here:  I understand the advantages of dual-porting a 
drive with a FC interface, but for SAS, exactly what are the advantages 
other than being able to read and write simultaneously (obviously, only 
from the on-drive cache). 


And yeah, these Seagates are dual-ported SAS. (according to the spec sheet)

Also, a 38% increase in IOPS without LESS drive cache seems unlikely.  
Or, at least highly workload-dependent.
Check that, they're claiming 38% better IOPS/watt over the SATA version, 
which, given that the SAS one pulls 10% more watts, means in absolute 
terms 45% or so.   I'm really skeptical that only an interface change 
can do that.



--
Erik Trimble
Java System Support
Mailstop:  usca22-123
Phone:  x17195
Santa Clara, CA

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Re: [zfs-discuss] "NearLine SAS"?

[Tim Cook]

On Tue, Jan 19, 2010 at 12:16 AM, Erik Trimble  wrote:

> A poster in another forum mentioned that Seagate (and Hitachi, amongst
> others) is now selling something labeled as "NearLine SAS" storage  (e.g.
> Seagate's NL35 series).
>
> Is it me, or does this look like nothing more than their standard 7200-rpm
> enterprise drives with a SAS or FC interface instead of a SATA one?
>
> I can't see any real advantage of those over the existing enterprise SATA
> drives (e.g. Seagate's Constellation ES series), other than not needing a
> FC/SAS->SATA gateway in the external drive enclosure.
>
>
>
Seagate claims the SAS versions of their drives actually see IOPS
improvements:
http://www.seagate.com/www/en-us/products/servers/barracuda_es/barracuda_es.2

If the SAS version is dual ported like I would expect, that's also a MAJOR
benefit.

-- 
--Tim
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[zfs-discuss] "NearLine SAS"?

[Erik Trimble]

A poster in another forum mentioned that Seagate (and Hitachi, amongst 
others) is now selling something labeled as "NearLine SAS" storage  
(e.g. Seagate's NL35 series).


Is it me, or does this look like nothing more than their standard 
7200-rpm enterprise drives with a SAS or FC interface instead of a SATA one?


I can't see any real advantage of those over the existing enterprise 
SATA drives (e.g. Seagate's Constellation ES series), other than not 
needing a FC/SAS->SATA gateway in the external drive enclosure.


--
Erik Trimble
Java System Support
Mailstop:  usca22-123
Phone:  x17195
Santa Clara, CA

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