Andrey Borzenkov wrote:
В Fri, 6 Sep 2013 09:32:19 +0200 (CEST) Jan Engelhardt <jengelh@inai.de> пишет:
On Thursday 2013-09-05 05:45, Linda Walsh wrote:
On POSIX (and linux), that blksize is the **preferred I/O size**. Which means it gets set based on the block-device and probably the filesystem.
A RAID uses stripe-size x width (#data stripes) as the "blksize" in the stat call.
So a RAID with 64k stripes & 12 data disks would have a stripe size of 768k. That stripsize is the optimal I/O size (and it isn't divisible by 2). I cannot reproduce this with at least MD RAIDs in modes 0 5 and 6 using 64k×12 devices. The filesystem created on it reports 4096 for st_blksize, as does fstat on a block device fd when directly opened. So if you can describe your RAID more thoroughly..
Out of interest - what /sys/block/mdX/queue/optimal_io_size says?
I don't have an mdX... it's hardware RAID... Setup w/15 disks total 3 groups of RAID5, so 4 data +1parity/group. The 3 groups are stripped like a RAID0 [ 2.754292] megasas: 06.506.00.00-rc1 Sat. Feb. 9 17:00:00 PDT 2013 [ 2.760727] megasas: 0x1000:0x0079:0x1000:0x9275: bus 5:slot 0:func 0 [ 2.767549] megasas: FW now in Ready state [ 2.771843] megaraid_sas 0000:05:00.0: irq 88 for MSI/MSI-X [ 2.835906] megasas_init_mfi: fw_support_ieee=0 [ 2.840312] megasas: INIT adapter done [ 2.906998] scsi0 : LSI SAS based MegaRAID driver [ 2.912046] megasas: 0x1000:0x0060:0x1028:0x1f0c: bus 2:slot 0:func 0 [ 2.918936] megasas: FW now in Ready state [ 2.925806] scsi 0:0:14:0: Enclosure LSI DE1600-SAS 0313 PQ: 0 ANSI: 5 [ 2.937228] scsi 0:0:15:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 2.948416] scsi 0:0:16:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 2.959674] scsi 0:0:17:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 2.966044] megasas_init_mfi: fw_support_ieee=0 [ 2.966044] megasas: INIT adapter done [ 2.979455] scsi 0:0:18:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 2.991140] scsi 0:0:19:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.002303] scsi 0:0:20:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.013486] scsi 0:0:21:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.024320] scsi 0:0:22:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.029128] scsi1 : LSI SAS based MegaRAID driver [ 3.040407] scsi 0:0:23:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.043045] scsi 1:0:8:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.043236] scsi 0:0:24:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.045904] scsi 1:0:9:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.046077] scsi 0:0:25:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.048589] scsi 0:0:26:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.048747] scsi 1:0:10:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.050180] scsi 0:0:27:0: Enclosure LSI DE1600-SAS 0313 PQ: 0 ANSI: 5 [ 3.051957] scsi 1:0:11:0: Direct-Access ATA Hitachi HDS72202 A28A PQ: 0 ANSI: 5 [ 3.053299] scsi 0:0:28:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.054807] scsi 1:0:12:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.056146] scsi 0:0:29:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.058992] scsi 0:0:30:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.061840] scsi 0:0:31:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.064680] scsi 0:0:32:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.280761] scsi 0:0:34:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.292011] scsi 0:0:35:0: Direct-Access ATA Hitachi HDS72202 A20N PQ: 0 ANSI: 5 [ 3.303268] scsi 0:0:36:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.314413] scsi 0:0:37:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.341222] scsi 1:0:32:0: Enclosure DP BACKPLANE 1.07 PQ: 0 ANSI: 5 [ 3.344068] scsi 0:0:38:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.346923] scsi 0:0:39:0: Direct-Access ATA Hitachi HUA72202 A3EA PQ: 0 ANSI: 5 [ 3.389002] scsi 0:2:0:0: Direct-Access LSI MR9280DE-8e 2.0. PQ: 0 ANSI: 5 [ 3.397434] scsi 0:2:1:0: Direct-Access LSI MR9280DE-8e 2.0. PQ: 0 ANSI: 5 ----- I don't know what you are looking for... I'm guessing that using a software RAID may not give the same results. -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org