SAS Expansion - Single Server + External Array vs. Twin Servers, for small network.

Allan74

Member
May 15, 2019
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Sorry guys, it's arts and crafts time again. A Pic can explain it better than I can without one...
As an aside,
the # of HDDs shown means nothing. They are for hardware representation only.

The Problem: Only 1x SFP+ 10g Port in Netgear MS510TX (my chosen LAN backbone).

I need to add Media storage and don't want too much complexity. This is Plex only. I don't care about 100% redundancy or 100% availability.
This is for a small home setup, with alot of storage. Never more than 3-4 *READ* clients at a time (only 1 Writer).
SEE IMAGE BELOW

Option 'A'
deploys 1 'complete' box, then external 6gb sff-8088 to sff-8088 on 'dumb box' 3gb SAS Expander.
(SAS 9280-4i4e, Internal 6gb Expander, sff-8088/sff-8088, External 3gb Expander).
In this config, each box gets 4 SAS lanes. *Management is easy*

Option 'B' deploys 2 'complete' boxes, each with it's own 2-port 10g NIC.
Primary to switch, bridge, 2nd Primary port to 2nd server.
(Each box with SAS 9261-8i, 10g NIC, SAS Expander(s))
In this config, each box gets 8 SAS lanes and 10g NIC, NIC#1 is bridged to connect NIC/BOX#2 and Switch.
*Matching SAS cards, can still use a single Win Console, but not ideal*

I currently have 99% of the hardware required *EXCEPT* for the HP 3gb SAS Expander, a powered Bitcoin Mining Riser (to power HP SAS Expander)
and whatever cables that I need to order once I decide on which route I am going. So essentially, about $100 out.

Other than sketchy performance, could someone make a good argument for NOT going with Option'A' ?

This is going to be the last hurrah for this particular hardware, as I have re-used it many times and plan on going to Solid State next year.
I also plan to stay with Windows and HW RAID, as I don't want to learn anything new....lol

As I have a current mix of SAS and SATA arrays in a couple boxes, should I use the 3gb Expander for my older 2TB SAS drives and use
the 6gb Expander for my newer/larger SATA drives ? or the other way around ?

thanks in advance. I am sure reading this trash was a chore.
Allan
storage_connectSM.jpg
 

i386

Well-Known Member
Mar 18, 2016
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I'm reading the options for the fifth time and I'm still not sure if I understand it correctly :D

Do you mean with option A one server that has a jbod/das connected to it?
And with option B a solution with two server where one holds all the data and the other connects to the switch?
 

kapone

Well-Known Member
May 23, 2015
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4 SAS lanes = 24gbps of bandwidth.

Your upstream LAN connection is 'only' 10gbps.

er... :)
 

gregsachs

Active Member
Aug 14, 2018
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I would personally avoid the HP 3 gb unit, look for one of the Intel expanders. You lose the external sff-8088 connection, but gain a better chipset. The intel also takes molex power.
 

Allan74

Member
May 15, 2019
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I'm reading the options for the fifth time and I'm still not sure if I understand it correctly
A= 1 media server + DAS. 4 SAS Lanes per box (single LSI 9280-4i4e card)
B= 2 media servers, server#1 sharing it's 10gb LAN connection. 8 SAS lanes per box.(each box with an LSI 9261-8i + LSI 6gb Expander)

This idea was spawned due to not wanting to get another switch and only having a single SFP+ in my current Netgear MS510TX.
Either way, all of my storage will connect via a single 10gb link to the network. I either limit the network or SAS lanes.
While I plan to cascade another switch off the MS510TX to get the rest of the house connected, it will either be a 1gb or 2.5gb at most.

I would personally avoid the HP 3 gb unit
I might just grab another IBM/Lenovo 6gb LSI Expander to match the one I currently have, then get one of these to solve my external input into the DAS:
Mini_SAS_SFF-8088_to_SFF-8087_Cable_Adapter__Low_Profile_PCI-480x480.jpg

So, other than using the old 3gb HP Expander (I will use another LSI 6gb and the bracket/cable above), can I run option A (single connection 4 SAS Lanes per 16+ Drive Expander) without feeling like I am cutting corners ?
 
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kapone

Well-Known Member
May 23, 2015
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So, other than using the old 3gb HP Expander (I will use another LSI 6gb and the bracket/cable above), can I run option A (single connection 4 SAS Lanes per 16+ Drive Expander) without feeling like I am cutting corners ?
You'll be just fine. I use 8 SAS lanes for 48 SAS HDDs and it doesn't even come close to using more than 20% usage... :)
 

Allan74

Member
May 15, 2019
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You'll be just fine. I use 8 SAS lanes for 48 SAS HDDs and it doesn't even come close to using more than 20% usage...
THAT is exactly what I wanted to read. Going the DAS road rather than another complete server is going to be far easier.
thanks for sharing your example.
 

Allan74

Member
May 15, 2019
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Lastly, since I need to grab another IBM/Lenovo SAS Expander, can anyone comment on the major differences/problems etc when comparing the 2 models available in the surplus market ?

IBM 46M0997 vs. Lenovo 03X3834

I currently own the IBM 46M0997 unit and have an IBM M5015/LSI 9260-8i/46M0851 to flash it with/from.
Should I just grab another IBM 46M0997 or scrap the current one and grab a pair of the Lenovo 03X3834 Expanders ?

Lenovo-IBM-SAS.jpg
 

BeTeP

Well-Known Member
Mar 23, 2019
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Both expanders use the same chipset family but their firmwares are based on different mainlines with different management features implemented. For most (like 99.99%) use cases those differences do not matter. What really matters is support (i.e. bugfixes). And the difference between the two boils down to the fact that Lenovo has not updated 03X3834 firmware since 2012 while they kept fixing 46M0997 until 2016.
 

Loto_Bak

New Member
Mar 10, 2011
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I would go option A

But don't bother with a expansion card... get a Netapp DS4246 off ebay. (Or a DS4486 for 48 disks)
They're usually quite cheap and great hardware.