Extremely slow rebuild

I had a 2TB drive fail and so I replaced it with at 3TB drive.  I started the rebuild process about 2 days ago and it's only at ~4%.  At this rate, it's estimating to be finished in about 90 days which is way too long.  I've attached my diagnostics file in hopes someone can help me get to the bottom of this.  Thanks.

Edit, the file is too large to attach: https://www.dropbox.com/s/zjyssxee8nwn16i/diagnostics-20160120-2017.zip?dl=0

Something isn't quite right with ATA 04 and ATA 05

Checked the drive cables and controller?

Jan 20 20:09:28 Tower kernel: ata4.00: cmd 25/00:98:a0:53:63/00:02:0e:00:00/e0 tag 0 dma 339968 in
Jan 20 20:09:28 Tower kernel:         res d0/23:02:02:00:00/00:00:40:03:d0/00 Emask 0x12 (ATA bus error)
Jan 20 20:09:28 Tower kernel: ata4.00: status: { Busy }
Jan 20 20:09:28 Tower kernel: ata4.00: error: { AMNF }
Jan 20 20:09:28 Tower kernel: ata4: hard resetting link
Jan 20 20:09:34 Tower kernel: ata4: SATA link up 1.5 Gbps (SStatus 113 SControl 10)
Jan 20 20:09:34 Tower kernel: ata4.00: configured for UDMA/33
Jan 20 20:09:34 Tower kernel: ata4: EH complete
Jan 20 20:09:34 Tower kernel: ata4: exception Emask 0x10 SAct 0x0 SErr 0x80000 action 0xe frozen
Jan 20 20:09:34 Tower kernel: ata4: irq_stat 0x00100010, PHY RDY changed
Jan 20 20:09:34 Tower kernel: ata4: SError: { 10B8B }
Jan 20 20:09:34 Tower kernel: ata4: hard resetting link
Jan 20 20:09:34 Tower kernel: ata5.00: exception Emask 0x50 SAct 0x0 SErr 0x4890800 action 0xe frozen
Jan 20 20:09:34 Tower kernel: ata5.00: irq_stat 0x0c400040, interface fatal error, connection status changed
Jan 20 20:09:34 Tower kernel: ata5: SError: { HostInt PHYRdyChg 10B8B LinkSeq DevExch }
Jan 20 20:09:34 Tower kernel: ata5.00: failed command: READ DMA EXT
Jan 20 20:09:34 Tower kernel: ata5.00: cmd 25/00:40:f8:5c:63/00:05:0e:00:00/e0 tag 16 dma 688128 in
Jan 20 20:09:34 Tower kernel:         res 50/00:00:f7:5c:63/00:00:0e:00:00/e0 Emask 0x50 (ATA bus error)
Jan 20 20:09:34 Tower kernel: ata5.00: status: { DRDY }
Jan 20 20:09:34 Tower kernel: ata5: hard resetting link
Jan 20 20:09:40 Tower kernel: ata4: SATA link up 1.5 Gbps (SStatus 113 SControl 10)
Jan 20 20:09:40 Tower kernel: ata4.00: configured for UDMA/33
Jan 20 20:09:40 Tower kernel: ata4: EH complete
Jan 20 20:09:40 Tower kernel: ata5: link is slow to respond, please be patient (ready=0)
Jan 20 20:09:41 Tower kernel: ata5: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd ef/10:06:00:00:00:00 (SET FEATURES) succeeded
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd f5/00:00:00:00:00:00 (SECURITY FREEZE LOCK) filtered out
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd b1/c1:00:00:00:00:00 (DEVICE CONFIGURATION OVERLAY) filtered out
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd ef/10:06:00:00:00:00 (SET FEATURES) succeeded
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd f5/00:00:00:00:00:00 (SECURITY FREEZE LOCK) filtered out
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd b1/c1:00:00:00:00:00 (DEVICE CONFIGURATION OVERLAY) filtered out
Jan 20 20:09:41 Tower kernel: ata5.00: configured for UDMA/33
Jan 20 20:09:41 Tower kernel: ata5: EH complete
Jan 20 20:09:41 Tower kernel: ata4.00: exception Emask 0x10 SAct 0x0 SErr 0x80000 action 0xe frozen
Jan 20 20:09:41 Tower kernel: ata4.00: irq_stat 0x00100010, PHY RDY changed

not much help, but I had a 2tb drive fail on me also (wd green), replaced with a 3tb drive (wd red), and it rebuilt in ~12hrs (iirc)

Something isn't quite right with ATA 04 and ATA 05

 

Checked the drive cables and controller?

 

Jan 20 20:09:28 Tower kernel: ata4.00: cmd 25/00:98:a0:53:63/00:02:0e:00:00/e0 tag 0 dma 339968 in
Jan 20 20:09:28 Tower kernel:         res d0/23:02:02:00:00/00:00:40:03:d0/00 Emask 0x12 (ATA bus error)
Jan 20 20:09:28 Tower kernel: ata4.00: status: { Busy }
Jan 20 20:09:28 Tower kernel: ata4.00: error: { AMNF }
Jan 20 20:09:28 Tower kernel: ata4: hard resetting link
Jan 20 20:09:34 Tower kernel: ata4: SATA link up 1.5 Gbps (SStatus 113 SControl 10)
Jan 20 20:09:34 Tower kernel: ata4.00: configured for UDMA/33
Jan 20 20:09:34 Tower kernel: ata4: EH complete
Jan 20 20:09:34 Tower kernel: ata4: exception Emask 0x10 SAct 0x0 SErr 0x80000 action 0xe frozen
Jan 20 20:09:34 Tower kernel: ata4: irq_stat 0x00100010, PHY RDY changed
Jan 20 20:09:34 Tower kernel: ata4: SError: { 10B8B }
Jan 20 20:09:34 Tower kernel: ata4: hard resetting link
Jan 20 20:09:34 Tower kernel: ata5.00: exception Emask 0x50 SAct 0x0 SErr 0x4890800 action 0xe frozen
Jan 20 20:09:34 Tower kernel: ata5.00: irq_stat 0x0c400040, interface fatal error, connection status changed
Jan 20 20:09:34 Tower kernel: ata5: SError: { HostInt PHYRdyChg 10B8B LinkSeq DevExch }
Jan 20 20:09:34 Tower kernel: ata5.00: failed command: READ DMA EXT
Jan 20 20:09:34 Tower kernel: ata5.00: cmd 25/00:40:f8:5c:63/00:05:0e:00:00/e0 tag 16 dma 688128 in
Jan 20 20:09:34 Tower kernel:         res 50/00:00:f7:5c:63/00:00:0e:00:00/e0 Emask 0x50 (ATA bus error)
Jan 20 20:09:34 Tower kernel: ata5.00: status: { DRDY }
Jan 20 20:09:34 Tower kernel: ata5: hard resetting link
Jan 20 20:09:40 Tower kernel: ata4: SATA link up 1.5 Gbps (SStatus 113 SControl 10)
Jan 20 20:09:40 Tower kernel: ata4.00: configured for UDMA/33
Jan 20 20:09:40 Tower kernel: ata4: EH complete
Jan 20 20:09:40 Tower kernel: ata5: link is slow to respond, please be patient (ready=0)
Jan 20 20:09:41 Tower kernel: ata5: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd ef/10:06:00:00:00:00 (SET FEATURES) succeeded
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd f5/00:00:00:00:00:00 (SECURITY FREEZE LOCK) filtered out
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd b1/c1:00:00:00:00:00 (DEVICE CONFIGURATION OVERLAY) filtered out
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd ef/10:06:00:00:00:00 (SET FEATURES) succeeded
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd f5/00:00:00:00:00:00 (SECURITY FREEZE LOCK) filtered out
Jan 20 20:09:41 Tower kernel: ata5.00: ACPI cmd b1/c1:00:00:00:00:00 (DEVICE CONFIGURATION OVERLAY) filtered out
Jan 20 20:09:41 Tower kernel: ata5.00: configured for UDMA/33
Jan 20 20:09:41 Tower kernel: ata5: EH complete
Jan 20 20:09:41 Tower kernel: ata4.00: exception Emask 0x10 SAct 0x0 SErr 0x80000 action 0xe frozen
Jan 20 20:09:41 Tower kernel: ata4.00: irq_stat 0x00100010, PHY RDY changed

Thanks for pointing that out!  I changed the cables and restarted the rebuild.  It went further in 30 minutes than it did the 3+ days I had it running previously (about 70mb/s).  I'm wondering if the original drive was reported as bad due to the cable issue...  I'll hook it up after the rebuild is done and re-integrate it back into my array.

Thanks again!

In your OP you said the drive failed. What exactly did you mean? unRAID will disable a drive when a write fails. This is often not a problem with the drive but with something else. unRAID V6 checks all drive SMART attributes and should indicate when they are the issue. When a drive is disabled and the drive is not the problem, you can rebuild it to itself without needing to use another drive.