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Rearranging SATA ports to boot SSD in ODD void


scruffters
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Hello chaps/chapesses,

 

Just a thought...

 

I know that running the gen8 in AHCI mode limits you to booting from hot swap 1 and 2 (or at least that is my understanding).

 

Also, while I have seen it work, I don't really like relying on a micro-SD for a boot loader.

 

As such, it occurred to me that one might be able to run an SSD located in the ODD void by re-routing port one on the the Mini-SAS break out loom, then simply routing the ODD SATA to the hot swap back plane.

 

As a ZFS user I am only interested in 1) AHCI 2) using the 4x hot swaps for HDDs (so I doubt the ODD port will slow my storage pool down at all).

 

Right now my microserver is on loan to a friend (so I can't test this to satisfy my curiosity), but my mind started to wonder if this isn't just the most obvious way to do things...

 

I see a lot of threads on here about this.

 

Any thoughts?

 

I'm sure I've missed something blatantly obvious...

Edited by scruffters
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I remember reading about someone who had done this, and I think it is possible.

 

Why not run the ODD port as a single drive raid array, and then set it as bootable?

 

I've used this method for both Linux and FreeNAS on my Gen8, and I don't need the micro SD card, trim works and speeds are quite good. The remaining ports then work as AHCI, and ZFS works great

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Is it actually possible to set the onboard (ODD) SATA port to RAID and the 4 drive cage ports as AHCI. I thought it's an all-or-nothing feature: either the B120i is in RAID mode or it's in AHCI.....

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With the B120i in "Raid Mode" any ports that aren't configured in a raid array run as AHCI.

 

I should also point out, from my investigations, it would appear a 1 drive raid array is shown to the OS as AHCI as well.

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With the B120i in "Raid Mode" any ports that aren't configured in a raid array run as AHCI.

 

I should also point out, from my investigations, it would appear a 1 drive raid array is shown to the OS as AHCI as well.

 

Are you certain about that? The reason I ask is because quite a few people have had trouble getting their drives recognized by the system with the B120i in RAID mode. Until they configure the drives to be in an array, even a single-drive RAID0, the system doesn't even recognize that the drives are connected. If they put the B120i into AHCI mode, the drives are recognized.

 

Is it possible you've flashed your G8 with some new BIOS version that makes this d0-able?

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Are you certain about that? The reason I ask is because quite a few people have had trouble getting their drives recognized by the system with the B120i in RAID mode. Until they configure the drives to be in an array, even a single-drive RAID0, the system doesn't even recognize that the drives are connected. If they put the B120i into AHCI mode, the drives are recognized.

 

Is it possible you've flashed your G8 with some new BIOS version that makes this d0-able?

I've only loaded what IP loaded (1.6 Bios I believe.)

 

I think there has been a lot of FUD around this, and I'm thinking I need to maybe make a bit of a "mythbusters" video around what does and doesn't happen.

 

The problem is that from what I can tell, there's no way to ask an OS "Hey, is drive X running in AHCI mode". You can ask if certain features are enabled, and interpolate from that.

 

My experience is:

b120i in "AHCI mode":

all drives show to Ubuntu 14.04, Ubuntu 14.10 and FreeNAS 9.3

You can't select the drive on SATA5 as the boot drive

 

b120i in "raid mode" with drive in SATA5 setup as a single drive raid array

all drives show to Ubuntu 14.04, 14.10 and FreeNAS 9.3 (and they show as their drive names, not as anything wierd like "Raid array 1" or anything like that.

you can then set the "raid array" as bootable, and then the system boots.

 

Output from Ubuntu

 

dmesg | grip -I ahci

 

scsi0 : ahci

scsi1 : ahci

scsi2 : ahci

scsi3 : ahci

scsi4 : ahci

scsi5 : ahci

 

Output from FreeNAS

 

pass4: <Samsung SSD 850 PRO 128GB EXM01B6Q> ATA-9 SATA 3.x device

pass4: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 512bytes)

 

protocol ATA/ATAPI-9 SATA 3.x

device model Samsung SSD 850 PRO 128GB

firmware revision EXM01B6Q

serial number S1SMNWAF811247T

WWN 50025388700220c1

cylinders 16383

heads 16

sectors/track 63

sector size logical 512, physical 512, offset 0

LBA supported 250069680 sectors

LBA48 supported 250069680 sectors

PIO supported PIO4

DMA supported WDMA2 UDMA6

media RPM non-rotating

 

Feature Support Enabled Value Vendor

read ahead yes yes

write cache yes yes

flush cache yes yes

overlap no

Tagged Command Queuing (TCQ) no no

Native Command Queuing (NCQ) yes 32 tags

NCQ Queue Management no

NCQ Streaming no

Receive & Send FPDMA Queued yes

SMART yes yes

microcode download yes yes

security yes no

power management yes yes

advanced power management no no

automatic acoustic management no no

media status notification no no

power-up in Standby no no

write-read-verify yes no 0/0x0

unload no no

general purpose logging yes yes

free-fall no no

Data Set Management (DSM/TRIM) yes

DSM - max 512byte blocks yes 8

DSM - deterministic read no

Host Protected Area (HPA) yes no 250069680/250069680

HPA - Security no

 

I should also point out, my SSD in a single drive raid array, when removed, was able to be read by another PC running the drive in AHCI mode as well.

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The question has to be asked (not that I'm posing it to you specifically; it's more of a generic "I wonder" question): will the drives show up in Windows (e.g. WHS2011, Server 2012(R2) )?

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Is it actually possible to set the onboard (ODD) SATA port to RAID and the 4 drive cage ports as AHCI. I thought it's an all-or-nothing feature: either the B120i is in RAID mode or it's in AHCI.....

No, you can not,,,

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That's the one I haven't tried yet, mainly because I don't have access to a copy (and I'm too tight to buy one!)

 

I could download the trial version and give that a blast I suppose.

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That absolutely would work. You would have 120 days to check it out ;)

 

I think you'll agree though, if the BIOS can see a drive, the OS should be able to see it.

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