SAS expander negotiating 1.5 Gb/s on some SATA drives 3 Gb/s on others

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Arcanum

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Jul 13, 2017
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I have a SC846E26-R1200B chasis with a SAS2008 PCI-Express Fusion-MPT SAS-2 controller. lsscsi is showing the expander as LSILOGIC SASX36 A.1. I noticed some of the drives (well I noticed the patter that it's just non WD ones) report only getting a 1.5 Gb/s SATA link. Any ideas?

Bash:
for m in {a..z}; do smartctl -a /dev/sd$m | grep 'SATA Version is\|Device Model'; done
Device Model:     ADATA SP920SS
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     ST12000VN0008-2PH103
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     WDC WD100EZAZ-11TDBA0
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 3.0 Gb/s)
Device Model:     ST12000VN0008-2PH103
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     ST10000NM001G-2MW103
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     ST12000VN0008-2PH103
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     WDC WD120EDAZ-11F3RA0
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 3.0 Gb/s)
Device Model:     Samsung SSD 850 EVO 250GB
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     ST12000NM0007-2A1101
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     ST10000NM0478-2H7100
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     WDC WD120EDAZ-11F3RA0
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 3.0 Gb/s)
Device Model:     ST10000NE0008-2JM101
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     WDC WD120EMFZ-11A6JA0
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 3.0 Gb/s)
Device Model:     ST12000VN0008-2PH103
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     WDC WD120EDAZ-11F3RA0
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 3.0 Gb/s)
Device Model:     ST10000NE0008-2JM101
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     ST10000NM001G-2MW103
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 1.5 Gb/s)
Device Model:     WDC WD120EMFZ-11A6JA0
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 3.0 Gb/s)
Device Model:     Samsung SSD 860 PRO 256GB
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 1.5 Gb/s)
 

Rain

Active Member
May 13, 2013
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Sounds like you have the SAS1 version of the expander backplane. The SAS1 expander is known to have issues with more than a few SATA disks and/or with SATA3 disks. The SAS2 and SAS3 expanders are much more performant and have much better compatibility with SATA disks.

Check the part number on the expander backplane. I'm suspecting it's BPN-SAS-846EL1.

I think you can replace the backplane with BPN-SAS2-846EL1 (note the "2"). Unfortunately, it's usually cheaper to buy the whole chassis with the correct backplane than it is to purchase the backplane separately.
 

Arcanum

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Jul 13, 2017
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Fair enough, it's probably not worth it to me to upgrade the chasis was dirt cheap so I guess I will just blame the SAS1 Expander. I was just wondering why the WD drives seem to work fine :)
 

Arcanum

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Jul 13, 2017
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I just now thought of doing a parallel dd read on all the drives and it's very close to just 6Gbit total. That sounds way too low even for a SAS1 backplane, sounds like I have a bottleneck somewhere that I need to remove frist.