Hello,
I have a sil 3124 PCI-X SATA card with 4 drives attached to it.
When I read simultaneously from all 4 drives, I get the expected
~220MB/s combined read speed, limited by the presence of a 32bit
card on the same bus (entire bus runs on 66mhz, mix of 64 and 32
bit cards). When I write to the drives however I only get half of
that ~106MB/s combined. Can someone shed some light?
All measurements are made on an idle system in single-user mode
Combined read:
root@Arzamas:~/tr# for d in sde sdb sdc sdd ; do dd if="/dev/${d}2" of=/dev/null count=500 bs=1M & done
[1] 30243
[2] 30244
[3] 30245
[4] 30246
root@Arzamas:~/tr# 500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 9.23146 s, 56.8 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 9.3649 s, 56.0 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 9.59152 s, 54.7 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 9.60045 s, 54.6 MB/s
Combined write:
root@Arzamas:~/tr# for d in sde sdb sdc sdd ; do dd of="/dev/${d}2" if=/dev/zero count=500 bs=1M & done
[1] 30239
[2] 30240
[3] 30241
[4] 30242
root@Arzamas:~/tr# 500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 19.4508 s, 27.0 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 19.6314 s, 26.7 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 19.7663 s, 26.5 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 19.7598 s, 26.5 MB/s
Individual read (making sure disks are good):
root@Arzamas:~/tr# for d in sde sdb sdc sdd ; do dd if="/dev/${d}2" of=/dev/null count=500 bs=1M ; done
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 5.00963 s, 105 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 5.15979 s, 102 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 5.19258 s, 101 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 5.24153 s, 100 MB/s
root@Arzamas:~/tr#
Individual write:
root@Arzamas:~/tr# for d in sde sdb sdc sdd ; do dd of="/dev/${d}2" if=/dev/zero count=500 bs=1M ; done
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 5.15325 s, 102 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 5.36731 s, 97.7 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 5.24908 s, 99.9 MB/s
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 5.36189 s, 97.8 MB/s
root@Arzamas:~/tr#
Card:
02:03.0 Mass storage controller: Silicon Image, Inc. SiI 3124 PCI-X Serial ATA Controller (rev 02)
Subsystem: Silicon Image, Inc. SiI 3124 PCI-X Serial ATA Controller
Control: I/O+ Mem+ BusMaster+ SpecCycle+ MemWINV+ VGASnoop- ParErr+ Stepping+ SERR+ FastB2B- DisINTx-
Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 64, Cache Line Size: 64 bytes
Interrupt: pin A routed to IRQ 25
Region 0: Memory at fc5fd800 (64-bit, non-prefetchable) [size=128]
Region 2: Memory at fc5f0000 (64-bit, non-prefetchable) [size=32K]
Region 4: I/O ports at bc00 [size=16]
Expansion ROM at fc480000 [disabled] [size=512K]
Capabilities: [64] Power Management version 2
Flags: PMEClk- DSI+ D1+ D2+ AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
Status: D0 PME-Enable- DSel=0 DScale=1 PME-
Capabilities: [40] PCI-X non-bridge device
Command: DPERE- ERO+ RBC=512 OST=12
Status: Dev=ff:1f.0 64bit+ 133MHz+ SCD- USC- DC=simple DMMRBC=2048 DMOST=12 DMCRS=128 RSCEM- 266MHz- 533MHz-
Capabilities: [54] MSI: Mask- 64bit+ Count=1/1 Enable-
Address: 0000000000000000 Data: 0000
Kernel driver in use: sata_sil24
Disks (excerpt from kernel bootup):
sata_sil24 0000:02:03.0: version 1.1
sata_sil24 0000:02:03.0: PCI INT A -> GSI 25 (level, low) -> IRQ 25
scsi3 : sata_sil24
scsi4 : sata_sil24
scsi5 : sata_sil24
scsi6 : sata_sil24
ata3: SATA max UDMA/100 host m128@0xfc5fd800 port 0xfc5f0000 irq 25
ata4: SATA max UDMA/100 host m128@0xfc5fd800 port 0xfc5f2000 irq 25
ata5: SATA max UDMA/100 host m128@0xfc5fd800 port 0xfc5f4000 irq 25
ata6: SATA max UDMA/100 host m128@0xfc5fd800 port 0xfc5f6000 irq 25
ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 0)
ata3.00: ATA-8: ST3500320NS, SN05, max UDMA/133
ata3.00: 976773168 sectors, multi 16: LBA48 NCQ (depth 31/32)
ata3.00: configured for UDMA/100
ata4: SATA link up 1.5 Gbps (SStatus 113 SControl 0)
ata4.00: ATA-8: ST3500320NS, SN05, max UDMA/133
ata4.00: 976773168 sectors, multi 16: LBA48 NCQ (depth 31/32)
ata4.00: configured for UDMA/100
ata5: SATA link up 1.5 Gbps (SStatus 113 SControl 0)
ata5.00: ATA-8: ST3500320NS, SN05, max UDMA/133
ata5.00: 976773168 sectors, multi 16: LBA48 NCQ (depth 31/32)
ata5.00: configured for UDMA/100
ata6: SATA link up 1.5 Gbps (SStatus 113 SControl 0)
ata6.00: ATA-8: ST3500320NS, SN05, max UDMA/133
ata6.00: 976773168 sectors, multi 16: LBA48 NCQ (depth 31/32)
ata6.00: configured for UDMA/100
scsi 3:0:0:0: Direct-Access ATA ST3500320NS SN05 PQ: 0 ANSI: 5
sd 3:0:0:0: [sdb] 976773168 512-byte hardware sectors (500108 MB)
sd 3:0:0:0: [sdb] Write Protect is off
sd 3:0:0:0: [sdb] Mode Sense: 00 3a 00 00
sd 3:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sd 3:0:0:0: [sdb] 976773168 512-byte hardware sectors (500108 MB)
sd 3:0:0:0: [sdb] Write Protect is off
sd 3:0:0:0: [sdb] Mode Sense: 00 3a 00 00
sd 3:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1 sdb2 sdb3
sd 3:0:0:0: [sdb] Attached SCSI disk
scsi 4:0:0:0: Direct-Access ATA ST3500320NS SN05 PQ: 0 ANSI: 5
sd 4:0:0:0: [sdc] 976773168 512-byte hardware sectors (500108 MB)
sd 4:0:0:0: [sdc] Write Protect is off
sd 4:0:0:0: [sdc] Mode Sense: 00 3a 00 00
sd 4:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sd 4:0:0:0: [sdc] 976773168 512-byte hardware sectors (500108 MB)
sd 4:0:0:0: [sdc] Write Protect is off
sd 4:0:0:0: [sdc] Mode Sense: 00 3a 00 00
sd 4:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sdc: sdc1 sdc2 sdc3
sd 4:0:0:0: [sdc] Attached SCSI disk
scsi 5:0:0:0: Direct-Access ATA ST3500320NS SN05 PQ: 0 ANSI: 5
sd 5:0:0:0: [sdd] 976773168 512-byte hardware sectors (500108 MB)
sd 5:0:0:0: [sdd] Write Protect is off
sd 5:0:0:0: [sdd] Mode Sense: 00 3a 00 00
sd 5:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sd 5:0:0:0: [sdd] 976773168 512-byte hardware sectors (500108 MB)
sd 5:0:0:0: [sdd] Write Protect is off
sd 5:0:0:0: [sdd] Mode Sense: 00 3a 00 00
sd 5:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sdd: sdd1 sdd2 sdd3
sd 5:0:0:0: [sdd] Attached SCSI disk
scsi 6:0:0:0: Direct-Access ATA ST3500320NS SN05 PQ: 0 ANSI: 5
sd 6:0:0:0: [sde] 976773168 512-byte hardware sectors (500108 MB)
sd 6:0:0:0: [sde] Write Protect is off
sd 6:0:0:0: [sde] Mode Sense: 00 3a 00 00
sd 6:0:0:0: [sde] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sd 6:0:0:0: [sde] 976773168 512-byte hardware sectors (500108 MB)
sd 6:0:0:0: [sde] Write Protect is off
sd 6:0:0:0: [sde] Mode Sense: 00 3a 00 00
sd 6:0:0:0: [sde] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sde: sde1 sde2 sde3
sd 6:0:0:0: [sde] Attached SCSI disk
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