seems i need to change the mail thread to
"why my RAID0 write speed so slow!" :P
i also use a Marvell 8 port PCI-X card. 8 SATA DISK RAID0, each single
disk can give me around 55MB/s, but the RAID0 can only give me 203MB/s.
I tried different io scheduler, all lead to same write speed at my side.
02:01.0 SCSI storage controller: Marvell MV88SX5081 8-port SATA I PCI-X
Controller (rev 03)
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop-
ParErr- Stepping- SERR- FastB2B-
Status: Cap+ 66Mhz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
Latency: 32, Cache Line Size 08
Interrupt: pin A routed to IRQ 24
Region 0: Memory at fa000000 (64-bit, non-prefetchable)
Capabilities: [40] Power Management version 2
Flags: PMEClk+ DSI- D1- D2- AuxCurrent=0mA PME
(D0-,D1-,D2-,D3hot-,D3cold-)
Status: D0 PME-Enable- DSel=0 DScale=0 PME-
Capabilities: [50] Message Signalled Interrupts: 64bit+
Queue=0/0 Enable-
Address: 0000000000000000 Data: 0000
Capabilities: [60] PCI-X non-bridge device.
Command: DPERE- ERO- RBC=0 OST=3
Status: Bus=2 Dev=1 Func=0 64bit+ 133MHz+ SCD- USC-,
DC=simple, DMMRBC=0, DMOST=3, DMCRS=0, RSCEM-
On Fri, 2005-08-26 at 09:51 +0200, Mirko Benz wrote:
> Hello,
>
> We have created a RAID 0 for the same environment:
> Personalities : [raid0] [raid5]
> md0 : active raid0 sdi[7] sdh[6] sdg[5] sdf[4] sde[3] sdd[2] sdc[1] sdb[0]
> 1250326528 blocks 64k chunks
>
Personalities : [linear] [raid0] [raid1] [raid5] [multipath] [raid6]
[raid10] [faulty]
md0 : active raid0 sdh[7] sdg[6] sdf[5] sde[4] sdd[3] sdc[2] sdb[1] sda
[0]
3125690368 blocks 64k chunks
SCSI disks: 400GB SATA
host: scsi11 Channel: 00 Id: 00 Lun: 00
Vendor: Hitachi Model: HDS724040KLSA80 Rev: KFAO
Type: Direct-Access ANSI SCSI revision: 03
> *** dd TEST ***
>
> time dd if=/dev/zero of=/dev/md0 bs=1M
> 14967373824 bytes transferred in 32,060497 seconds (466847843 bytes/sec)
>
> iostat 5 output:
> avg-cpu: %user %nice %sys %iowait %idle
> 0,00 0,00 89,60 9,50 0,90
>
> Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
> hda 0,00 0,00 0,00 0 0
> sda 0,00 0,00 0,00 0 0
> sdb 455,31 0,00 116559,52 0 581632
> sdc 455,51 0,00 116540,28 0 581536
> sdd 450,10 0,00 116545,09 0 581560
> sde 454,11 0,00 116559,52 0 581632
> sdf 452,30 0,00 116559,52 0 581632
> sdg 454,71 0,00 116553,11 0 581600
> sdh 453,31 0,00 116533,87 0 581504
> sdi 453,91 0,00 116556,31 0 581616
> sdj 0,00 0,00 0,00 0 0
> sdk 0,00 0,00 0,00 0 0
> sdl 0,00 0,00 0,00 0 0
> sdm 0,00 0,00 0,00 0 0
> sdn 0,00 0,00 0,00 0 0
> md0 116556,11 0,00 932448,90 0 4652920
>
> Comments: 466 MB / 8 = 58,25 MB/s which is about the same as a dd to a
> single disk (58,5 MB/s). So the controller + I/O subsystem is not the
> bottleneck.
>
> Regards,
> Mirko
>
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