Comments on: SAS smacks down FC http://storageadvisors.adaptec.com/2005/10/28/41/ Storage Solutions for Real World IT Professionals Sat, 20 Mar 2010 05:54:50 +0000 http://wordpress.org/?v=1.5.2 Comment on SAS smacks down FC by: Tom http://storageadvisors.adaptec.com/2005/10/28/41/#comment-69 Sat, 03 Dec 2005 13:07:10 +0000 http://storageadvisors.adaptec.com/2005/10/28/41/#comment-69 Joe, Yes, yes, and yes! :-) Regarding FC, it's of course moving to 4Gb/s, but it just seems too late. As you point out, it would take only 4 drives to saturate a 4Gb FC bus. Regarding wide ports on SAS, yeah, I just love the idea of 12Gb/s going to 24Gb/s in the next few years. And I suppose SAS could go wider than 4X very easily. Smokin'! Regarding SAS clustering, what are you hearing about Microsoft clustering, and it no longer being allowed with PCI RAID? (See previous post <a href="http://storageadvisors.adaptec.com/2005/10/24/is-pci-raid-clustering-finally-dead/">here</a>.) Sounds like we need SAS-to-SAS RAID controllers. Do you agree? Damn good to hear from you, buddy. Keep in touch. TT Joe,

Yes, yes, and yes! :-)

Regarding FC, it’s of course moving to 4Gb/s, but it just seems too late. As you point out, it would take only 4 drives to saturate a 4Gb FC bus.

Regarding wide ports on SAS, yeah, I just love the idea of 12Gb/s going to 24Gb/s in the next few years. And I suppose SAS could go wider than 4X very easily. Smokin’!

Regarding SAS clustering, what are you hearing about Microsoft clustering, and it no longer being allowed with PCI RAID? (See previous post here.) Sounds like we need SAS-to-SAS RAID controllers. Do you agree?

Damn good to hear from you, buddy. Keep in touch.

TT

]]> Comment on SAS smacks down FC by: Joe Fagan http://storageadvisors.adaptec.com/2005/10/28/41/#comment-67 Sat, 03 Dec 2005 03:14:59 +0000 http://storageadvisors.adaptec.com/2005/10/28/41/#comment-67 Tom, About SAS as a fabric and an interconnect. 2 or more points I'd like to add. 1) FC as a drive interconnect has shared bandwidth between all the devices so any amount of sequential disk I/O (with Maxtor Atas 15K II SAS at the WORLD RECORD of 98MB/s) is going to saturate the FC shared bus. SAS on the otherhand is point to point at 3ooMB/s (full duplex unlike our FC and SATA hald -duplex buddies) 2) SAS supports Wide Ports, which means that bandwidth is scalable and almost unbounded. For more bandwidth just add more connections (up to 128 of them)! Doubling the number of connections from the server to the storage cabinet or expander doubles the bandwidth between them and so the connection back to the host, or from expander to expander will never become a bottleneck. Yes, FC has port aggregation but its done back at the driver level. SAS implements wide lanes at the port layer and is transparent to the driver level. 3) SAS supports multi-initiator and so many servers can be clustered to provide performance and/or server fault tolerance. If you look at the majority of clusters today, they are FC based - WHY? ...because there's NO alternative - until SAS. For an "in-the-rack" cluster with 2-5 server or server blades, 1 or 2 storage cabinets with 1-2 fanout expanders the cost effectiveness of SAS over FC is compelling. Joe Tom,

About SAS as a fabric and an interconnect. 2 or more points I’d like to add.

1) FC as a drive interconnect has shared bandwidth between all the devices so any amount of sequential disk I/O (with Maxtor Atas 15K II SAS at the WORLD RECORD of 98MB/s) is going to saturate the FC shared bus. SAS on the otherhand is point to point at 3ooMB/s (full duplex unlike our FC and SATA hald -duplex buddies)

2) SAS supports Wide Ports, which means that bandwidth is scalable and almost unbounded. For more bandwidth just add more connections (up to 128 of them)! Doubling the number of connections from the server to the storage cabinet or expander doubles the bandwidth between them and so the connection back to the host, or from expander to expander will never become a bottleneck. Yes, FC has port aggregation but its done back at the driver level. SAS implements wide lanes at the port layer and is transparent to the driver level.

3) SAS supports multi-initiator and so many servers can be clustered to provide performance and/or server fault tolerance. If you look at the majority of clusters today, they are FC based - WHY? …because there’s NO alternative - until SAS. For an “in-the-rack” cluster with 2-5 server or server blades, 1 or 2 storage cabinets with 1-2 fanout expanders the cost effectiveness of SAS over FC is compelling.

Joe

]]> Comment on SAS smacks down FC by: Tom http://storageadvisors.adaptec.com/2005/10/28/41/#comment-25 Wed, 02 Nov 2005 19:12:49 +0000 http://storageadvisors.adaptec.com/2005/10/28/41/#comment-25 Sorry about that, Joe. My template for new posts starts out with "Joe, you couldn't be more wrong". I guess I forgot to delete it this time. ;-) TT Sorry about that, Joe. My template for new posts starts out with “Joe, you couldn’t be more wrong”. I guess I forgot to delete it this time. ;-)

TT

]]> Comment on SAS smacks down FC by: Joe http://storageadvisors.adaptec.com/2005/10/28/41/#comment-14 Sat, 29 Oct 2005 19:29:43 +0000 http://storageadvisors.adaptec.com/2005/10/28/41/#comment-14 TT, As much as I'd love to disagree with you... I don't! Oh well - we'll fight another day. If you check out one of my <a href="http://storageadvisors.adaptec.com/2005/10/14/scsi-fc-iscsi-and-sas/" rel="nofollow">see previous blogs</a> you'll see I actually mention the SAS interconnect as well. I was speaking strictly to SAS drives relative to other drives. You're right on the SAS interconnect front. In fact, I'll go as far as to say that the interconnect technology and SAS switches, when they turn up, will be more disruptive to the storage industry then the drives themselves. No worries though - I'm sure we'll disagree soon! :-) Blog ya later! Joe TT,

As much as I’d love to disagree with you… I don’t! Oh well - we’ll fight another day. If you check out one of my see previous blogs you’ll see I actually mention the SAS interconnect as well. I was speaking strictly to SAS drives relative to other drives.

You’re right on the SAS interconnect front. In fact, I’ll go as far as to say that the interconnect technology and SAS switches, when they turn up, will be more disruptive to the storage industry then the drives themselves.

No worries though - I’m sure we’ll disagree soon! :-)

Blog ya later!

Joe

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