RAID a strip size

Pavel Kankovsky peak na argo.troja.mff.cuni.cz
Pátek Listopad 8 09:32:55 CET 2002


On Thu, 7 Nov 2002, Dalibor Toman wrote:

> Podle experimentu se zda, ze je pri cteni kratsich bloku vyhodnejsi
> snizit stripsize (cteni/zapis se rozlozi na vice disku). Bohuzel
> netusim jak pristupuje k disku postgres.

Driver pro Adaptecy (a i nektere dalsi drivery) pisou ve svem
/proc/scsi/... statistiku operaci podle delky, napr.:

(scsi0:0:0:0)
  Device using Wide/Sync transfers at 160.0 MByte/sec, offset 31
  Transinfo settings: current(9/31/1/2), goal(9/127/1/2), user(9/127/1/2)
  Total transfers 2691637 (255673 reads and 2435964 writes)
             < 2K      2K+     4K+     8K+    16K+    32K+    64K+   128K+
   Reads:    8794     361  191152   25040   14729    6865    8732       0
  Writes: 1149306  171419  790439  258574   17878    9368   38980       0

Mozna ze podobnou vec umi i pouzivany driver. (Nebo to do nej lze dopsat
<g>.)

--Pavel Kankovsky aka Peak
"Welcome to the Czech Republic. Bring your own lifeboats."




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