Date: Thu, 2 Jun 2022 13:14:52 -0700 From: David Christensen <dpchrist@holgerdanske.com> To: questions@freebsd.org Subject: Re: Effect of using SATA 2.x and 3.x in zfs mirrored config Message-ID: <8dcf342c-74f6-242d-338b-1c8cd2dee54f@holgerdanske.com> In-Reply-To: <1706301853.51806224.1654176891423.JavaMail.zimbra@shaw.ca> References: <1706301853.51806224.1654176891423.JavaMail.zimbra@shaw.ca>
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On 6/2/22 06:34, Dale Scott wrote: > Hi all, I installed FreeBSD "root-on-zfs" using the installer on two new WD Blue 1TB SSDs (mirrored). > > Looking in dmesg, I see one of the drives is using SATA 3 (600MB/s transfer), and the other is using SATA 2 (300MB/s transfer). Will mixing SATA 2 and SATA 3 drives cause any technical issues? Is there any reason why I should use SATA 2 for both drives? > > The system was an enterprise castoff circa 2011 HP 6200 Pro Microtower (i7-2600 CPU). I naievely thought there were four identical SATA ports and plugged in the two SSDs, a rotating drive, and a DVD. However, looking now in the illustrated parts guide I see only one port is SATA 3. > > SATA0 1st hard drive (SATA 3.0) > SATA1 2nd hard drive (SATA 2.0) > SATA2 1st optical drive (SATA 2.0) > ESATA eSATA connector > > From dmesg: > > ada0: <WDC WDS100T2B0A-00SM50 415020WD> ACS-4 ATA SATA 3.x device > ada0: Serial Number 21401J801472 > ada0: 600.000MB/s transfers (SATA 3.x, UDMA5, PIO 512bytes) > ada0: 953869MB (1953525168 512 byte sectors) > > ada1: <WDC WDS100T2B0A-00SM50 415020WD> ACS-4 ATA SATA 3.x device > ada1: Serial Number 214036801110 > ada1: 300.000MB/s transfers (SATA 2.x, UDMA5, PIO 512bytes) > ada1: 953869MB (1953525168 512 byte sectors) > > ada2 at ata2 bus 0 scbus2 target 0 lun 0 > ada2: <ST31000322CS SC13> ATA8-ACS SATA 2.x device > ada2: Serial Number 5VX2H84K > ada2: 300.000MB/s transfers (SATA 2.x, UDMA5, PIO 8192bytes) > ada2: 953869MB (1953525168 512 byte sectors) > > cd0 at ata0 bus 0 scbus0 target 1 lun 0 > cd0: <hp DVD-RAM GH80N RF03> Removable CD-ROM SCSI device > cd0: Serial Number 217CD060574 > cd0: 150.000MB/s transfers (SATA 1.x, UDMA5, ATAPI 12bytes, PIO 8192bytes) > cd0: Attempt to query device size failed: NOT READY, Medium not present - tray c > > > Thanks, > Dale I do not know if the SATA 3 Gbps vs. 6 Gbps mismatch will break ZFS. If the computer boots and runs, I would hammer it with filesystem benchmarks. dbench(1) comes to mind. It appears that computer has PCIe 1.0 (2.5 Gbps per channel): https://support.hp.com/us-en/document/c02779499 Perhaps a PCIe x4 to SATA 6 Gbps HBA that is backwards compatible with PCIe 1.0 could run a single SATA 6 Gbps SSD at full speed (?). You could ask around with various manufacturers' technical support, or just buy a card and find out: https://docs.broadcom.com/doc/12353332 David
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