InstantForum.NET v2.9.0SQLServerCentralhttp://www.sqlservercentral.com/Forums/notifications@sqlservercentral.comSat, 25 May 2013 14:52:19 GMT20http://www.sqlservercentral.com/Forums/Topic1391933-391-1.aspx[quote][b]ESAT ERKEC (12/5/2012)[/b][hr]Task Manager -> Resource Monitor ->Disk-> Filter the sql server.exe and then look at the ratio can you see mdf and ldf file of mirror db....for windows 2008 server[/quote]Yep had a look at that sqlservr.exe is at the top writing to the mirrorDB.mdf 400,000 - 1,296,531 Write(B/Sec)Followed by the log file writes around 24,104 (B/Sec)Wed, 05 Dec 2012 02:06:39 GMTbugghttp://www.sqlservercentral.com/Forums/Topic1391933-391-1.aspxTask Manager -> Resource Monitor ->Disk-> Filter the sql server.exe and then look at the ratio can you see mdf and ldf file of mirror db....for windows 2008 serverWed, 05 Dec 2012 00:53:13 GMTESAT ERKEChttp://www.sqlservercentral.com/Forums/Topic1391933-391-1.aspxAnyone have any suggestions? What other things I may check to see what the bottleneck is?ThanksTue, 04 Dec 2012 14:18:54 GMTbugghttp://www.sqlservercentral.com/Forums/Topic1391933-391-1.aspxOkay I've done a bit of digging and its more than likely the mirrored db that is causing the high I/O disk activity. Below are the stats ive collectedInfo gathered from dm server stats[quote]db , file_type , io_mb , io_stall_s , io_stall_pct rn ,DB_Mirror , data , 919078.42 , 2765993.62 , 83.74 , 1DB_Mirror , log , 58954.74 , 291365.28, 8.82 , 2tempdb , data , 11838.19 , 135767.98, 4.11 3audit , data , 24905.06 , 47932.41, 1.45 , 4[/quote]-- Average stalls per read, per write, and per total input/output-- for each database file.[quote]DB , io_stall_read_ms , num_of_reads , avg_read_stall_ms, io_stall_write_ms , num_of_writes , avg_write_stall_ms , io_stalls , total_io , avg_io_stall_mstempdb , 1404523 , 97861 , 14.4 , 134363460 , 99434 , 1351.3 , 135767983 , 197295 , 688.1 ,audit , 47643279 , 336573 , 141.6 , 289131 , 18395 , 15.7 , 47932410 , 354968 , 135.0tempdb , 175 , 86 , 2.0 , 832179 , 7247 , 114.8 , 832354 , 7333 , 113.5DB_DEV , 20520495 , 516235 , 39.8 , 465210 , 21856 , 21.3 , 20985705 , 538091 , 39.0 ,DB_Mirror , 33367858 , 2718983 , 12.3 , 2732894677 , 99223544 , 27.5 , 2766262535 , 101942527 , 27.1[/quote]There doesn't seem to be any pending I/O requests by file.[u]Info from Perfmon counters[/u]These don’t seem to say the disk is over loaded? As there are below 20ms• Avg. Disk sec/write: Avergae = 0.015 -> 15ms• Avg. Disk sec/read: Avergae = 0.004 -> 4ms• Avg. Disk sec/read: Transfer = 0.005 -> 5ms% Disk Time: Average = 84.793 msAverage Disk queue length = 1.150-> 115.0msThe Resource monitor shows sqlserv.exe total(Read & writes) as (B/sec) 466,828 to the DB_mirror.mdfI did discover that Tempdb, All Data files and Log files are all on the same hard drive which will impact performance .Do think moving these to separate hard drives will help? and would it help more if they were solid state hard drives?Does anyone know other things i can look at to determine the disk I/O bottlenecks?ThanksTue, 04 Dec 2012 05:56:15 GMTbugghttp://www.sqlservercentral.com/Forums/Topic1391933-391-1.aspxHi,Should my mirror server hard disk I/O utilization be between 90% and 100%. ? I understand its the mirror server and the hard disk is constantly getting written to but should it be this high?ThanksMon, 03 Dec 2012 07:17:43 GMTbugg