I have an AM2 motherboard with onboard SB600 AHCI, connected to 10 identical 2 TB hard drives: - 4 from the onboard SB600 (sd[abcd]) - 2 from the motherboard PDC42819 (sd[ef]) - 4 from a Si3132 PCIe card (sd[ghij]) I can copy (RAID resync, actually) from sda to sdc (or sdb to sdd) at around 100 MB/s. But copying sda to sde (or sdb to sdf) runs around 25-33 MB/s. Copying to the Si3132 drices is also reasonably fast. This is very annoying. Same drives, same kernel, same driver (AHCI), same queue depth (31), same write cache settings (on; I have a good UPS and I'll take the risk while a resync is minimizing a different risk). Same drive firmware version, even (Hitachi HDS722020ALA330, FwRev=JKAOA3EA). The one difference I notice is the multicount setting: /dev/sda: multcount = 16 (on) /dev/sdb: multcount = 16 (on) /dev/sdc: multcount = 16 (on) /dev/sdd: multcount = 16 (on) /dev/sde: multcount = 0 (off) /dev/sdf: multcount = 0 (off) /dev/sdg: multcount = 0 (off) /dev/sdh: multcount = 0 (off) /dev/sdi: multcount = 16 (on) /dev/sdj: multcount = 16 (on) "hdparm -m16 /dev/sde" gives me a rather threatening warning. If I ignore it and force it anyway, the setting is accepted, but there's no apparent speed difference. :-( I can also *read* from all drives at 110 MB/s. It's only writes that differ. Is there a good place to start debugging this? Here's the lspci -nn output: 00:12.0 SATA controller [0106]: ATI Technologies Inc SB600 Non-Raid-5 SATA [1002:4380] 01:00.0 Mass storage controller [0180]: Silicon Image, Inc. SiI 3132 Serial ATA Raid II Controller [1095:3132] (rev 01) 02:00.0 Mass storage controller [0180]: Silicon Image, Inc. SiI 3132 Serial ATA Raid II Controller [1095:3132] (rev 01) 04:00.0 RAID bus controller [0104]: Promise Technology, Inc. PDC42819 [FastTrak TX2650/TX4650] [105a:3f20] And the relevant boot messages: libata version 3.00 loaded. ahci 0000:00:12.0: version 3.0 ahci 0000:00:12.0: PCI INT A -> GSI 22 (level, low) -> IRQ 22 ahci 0000:00:12.0: MSI K9A2 Platinum: enabling 64bit DMA ahci 0000:00:12.0: AHCI 0001.0100 32 slots 4 ports 3 Gbps 0xf impl SATA mode ahci 0000:00:12.0: flags: 64bit ncq sntf ilck pm led clo pmp pio slum part ccc scsi0 : ahci scsi1 : ahci scsi2 : ahci scsi3 : ahci ata1: SATA max UDMA/133 irq_stat 0x00400040, connection status changed irq 22 ata2: SATA max UDMA/133 irq_stat 0x00400040, connection status changed irq 22 ata3: SATA max UDMA/133 irq_stat 0x00400000, PHY RDY changed irq 22 ata4: SATA max UDMA/133 abar m1024@0xfe5ff800 port 0xfe5ffa80 irq 22 ahci 0000:04:00.0: PDC42819 can only drive SATA devices with this driver ahci 0000:04:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17 ahci 0000:04:00.0: AHCI 0001.0100 32 slots 4 ports 3 Gbps 0xf impl RAID mode ahci 0000:04:00.0: flags: 64bit ncq sntf ilck pm led clo pmp pio slum part ccc ahci 0000:04:00.0: setting latency timer to 64 scsi4 : ahci scsi5 : ahci scsi6 : ahci scsi7 : ahci ata5: SATA max UDMA/133 abar m8192@0xfe9fc000 port 0xfe9fc100 irq 17 ata6: SATA max UDMA/133 abar m8192@0xfe9fc000 port 0xfe9fc180 irq 17 ata7: SATA max UDMA/133 abar m8192@0xfe9fc000 port 0xfe9fc200 irq 17 ata8: SATA max UDMA/133 abar m8192@0xfe9fc000 port 0xfe9fc280 irq 17 sata_sil24 0000:01:00.0: version 1.1 sata_sil24 0000:01:00.0: PCI INT A -> GSI 19 (level, low) -> IRQ 19 sata_sil24 0000:01:00.0: setting latency timer to 64 scsi8 : sata_sil24 scsi9 : sata_sil24 ata9: SATA max UDMA/100 host m128@0xfe6ffc00 port 0xfe6f8000 irq 19 ata10: SATA max UDMA/100 host m128@0xfe6ffc00 port 0xfe6fa000 irq 19 sata_sil24 0000:02:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 sata_sil24 0000:02:00.0: setting latency timer to 64 scsi10 : sata_sil24 scsi11 : sata_sil24 ata11: SATA max UDMA/100 host m128@0xfe7ffc00 port 0xfe7f8000 irq 16 ata12: SATA max UDMA/100 host m128@0xfe7ffc00 port 0xfe7fa000 irq 16 ata8: SATA link down (SStatus 0 SControl 300) ata7: SATA link down (SStatus 0 SControl 300) ata6: SATA link up 3.0 Gbps (SStatus 123 SControl 300) ata6.00: ATA-8: Hitachi HDS722020ALA330, JKAOA3EA, max UDMA/133 ata6.00: 3907029168 sectors, multi 0: LBA48 NCQ (depth 31/32), AA ata6.00: configured for UDMA/133 ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300) ata5.00: ATA-8: Hitachi HDS722020ALA330, JKAOA3EA, max UDMA/133 ata5.00: 3907029168 sectors, multi 0: LBA48 NCQ (depth 31/32), AA ata5.00: configured for UDMA/133 ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 300) ata4.00: ATA-8: Hitachi HDS722020ALA330, JKAOA3EA, max UDMA/133 ata4.00: 3907029168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA ata4.00: SB600 AHCI: limiting to 255 sectors per cmd ata4.00: SB600 AHCI: limiting to 255 sectors per cmd ata4.00: configured for UDMA/133 ata2: softreset failed (device not ready) ata3: softreset failed (device not ready) ata3: applying SB600 PMP SRST workaround and retrying ata1: softreset failed (device not ready) ata1: applying SB600 PMP SRST workaround and retrying ata2: applying SB600 PMP SRST workaround and retrying ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300) ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300) ata3.00: ATA-8: Hitachi HDS722020ALA330, JKAOA3EA, max UDMA/133 ata3.00: 3907029168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA ata3.00: SB600 AHCI: limiting to 255 sectors per cmd ata3.00: configured for UDMA/133 ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300) ata2.00: ATA-8: Hitachi HDS722020ALA330, JKAOA3EA, max UDMA/133 ata2.00: 3907029168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA ata2.00: SB600 AHCI: limiting to 255 sectors per cmd ata2.00: SB600 AHCI: limiting to 255 sectors per cmd ata2.00: configured for UDMA/133 ata1.00: ATA-8: Hitachi HDS722020ALA330, JKAOA3EA, max UDMA/133 ata1.00: 3907029168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA ata1.00: SB600 AHCI: limiting to 255 sectors per cmd ata1.00: SB600 AHCI: limiting to 255 sectors per cmd ata1.00: configured for UDMA/133 scsi 0:0:0:0: Direct-Access ATA Hitachi HDS72202 JKAO PQ: 0 ANSI: 5 sd 0:0:0:0: [sda] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) scsi 1:0:0:0: Direct-Access ATA Hitachi HDS72202 JKAO PQ: 0 ANSI: 5 sd 1:0:0:0: [sdb] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) scsi 2:0:0:0: Direct-Access ATA Hitachi HDS72202 JKAO PQ: 0 ANSI: 5 sd 1:0:0:0: [sdb] Write Protect is off sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 10 sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, supports DPO and FUA sd 2:0:0:0: [sdc] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) sd 2:0:0:0: [sdc] Write Protect is off sd 2:0:0:0: [sdc] Mode Sense: 00 3a 00 10 sd 2:0:0:0: [sdc] Write cache: enabled, read cache: enabled, supports DPO and FUA scsi 3:0:0:0: Direct-Access ATA Hitachi HDS72202 JKAO PQ: 0 ANSI: 5 sd 3:0:0:0: [sdd] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) scsi 4:0:0:0: Direct-Access ATA Hitachi HDS72202 JKAO PQ: 0 ANSI: 5 sd 3:0:0:0: [sdd] Write Protect is off sd 3:0:0:0: [sdd] Mode Sense: 00 3a 00 10 sd 3:0:0:0: [sdd] Write cache: enabled, read cache: enabled, supports DPO and FUA sd 4:0:0:0: [sde] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) sd 4:0:0:0: [sde] Write Protect is off sd 4:0:0:0: [sde] Mode Sense: 00 3a 00 10 scsi 5:0:0:0: Direct-Access ATA Hitachi HDS72202 JKAO PQ: 0 ANSI: 5 sd 4:0:0:0: [sde] Write cache: enabled, read cache: enabled, supports DPO and FUA sd 5:0:0:0: [sdf] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) sd 5:0:0:0: [sdf] Write Protect is off sd 5:0:0:0: [sdf] Mode Sense: 00 3a 00 10 sd 5:0:0:0: [sdf] Write cache: enabled, read cache: enabled, supports DPO and FUA sdc: sdc1 sdc2 sdc3 sdc4 sdd: sdd1 sdd2 sdd3 sdd4 sdb: sdb1 sdb2 sdb3 sdb4 sde: sde1 sde2 sde3 sde4 sdf: sdf1 sdf2 sdf3 sdf4 sd 0:0:0:0: [sda] Write Protect is off sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 10 sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, supports DPO and FUA sd 2:0:0:0: [sdc] Attached SCSI disk sd 1:0:0:0: [sdb] Attached SCSI disk sd 3:0:0:0: [sdd] Attached SCSI disk sd 5:0:0:0: [sdf] Attached SCSI disk sd 4:0:0:0: [sde] Attached SCSI disk sda: sda1 sda2 sda3 sda4 sd 0:0:0:0: [sda] Attached SCSI disk ata9: SATA link up 3.0 Gbps (SStatus 123 SControl 0) ata9.00: ATA-8: Hitachi HDS722020ALA330, JKAOA3EA, max UDMA/133 ata9.00: 3907029168 sectors, multi 0: LBA48 NCQ (depth 31/32) ata11: SATA link up 3.0 Gbps (SStatus 123 SControl 0) ata9.00: configured for UDMA/100 scsi 8:0:0:0: Direct-Access ATA Hitachi HDS72202 JKAO PQ: 0 ANSI: 5 sd 8:0:0:0: [sdg] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) sd 8:0:0:0: [sdg] Write Protect is off sd 8:0:0:0: [sdg] Mode Sense: 00 3a 00 10 sd 8:0:0:0: [sdg] Write cache: enabled, read cache: enabled, supports DPO and FUA ata11.00: ATA-8: Hitachi HDS722020ALA330, JKAOA3EA, max UDMA/133 ata11.00: 3907029168 sectors, multi 16: LBA48 NCQ (depth 31/32) sdg: sdg1 sdg2 sdg3 sdg4 sd 8:0:0:0: [sdg] Attached SCSI disk ata11.00: configured for UDMA/100 ata10: SATA link up 3.0 Gbps (SStatus 123 SControl 0) ata10.00: ATA-8: Hitachi HDS722020ALA330, JKAOA3EA, max UDMA/133 ata10.00: 3907029168 sectors, multi 0: LBA48 NCQ (depth 31/32) ata10.00: configured for UDMA/100 scsi 9:0:0:0: Direct-Access ATA Hitachi HDS72202 JKAO PQ: 0 ANSI: 5 sd 9:0:0:0: [sdh] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) scsi 10:0:0:0: Direct-Access ATA Hitachi HDS72202 JKAO PQ: 0 ANSI: 5 sd 10:0:0:0: [sdi] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) sd 10:0:0:0: [sdi] Write Protect is off sd 10:0:0:0: [sdi] Mode Sense: 00 3a 00 10 sd 10:0:0:0: [sdi] Write cache: enabled, read cache: enabled, supports DPO and FUA sdi: sdi1 sdi2 sdi3 sdi4 sd 9:0:0:0: [sdh] Write Protect is off sd 10:0:0:0: [sdi] Attached SCSI disk sd 9:0:0:0: [sdh] Mode Sense: 00 3a 00 10 sd 9:0:0:0: [sdh] Write cache: enabled, read cache: enabled, supports DPO and FUA sdh: sdh1 sdh2 sdh3 sdh4 sd 9:0:0:0: [sdh] Attached SCSI disk ata12: SATA link up 3.0 Gbps (SStatus 123 SControl 0) ata12.00: ATA-8: Hitachi HDS722020ALA330, JKAOA3EA, max UDMA/133 ata12.00: 3907029168 sectors, multi 16: LBA48 NCQ (depth 31/32) ata12.00: configured for UDMA/100 scsi 11:0:0:0: Direct-Access ATA Hitachi HDS72202 JKAO PQ: 0 ANSI: 5 sd 11:0:0:0: [sdj] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) sd 11:0:0:0: [sdj] Write Protect is off sd 11:0:0:0: [sdj] Mode Sense: 00 3a 00 10 sd 11:0:0:0: [sdj] Write cache: enabled, read cache: enabled, supports DPO and FUA sdj: sdj1 sdj2 sdj3 sdj4 sd 11:0:0:0: [sdj] Attached SCSI disk -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
