Date: Fri, 25 Oct 2013 23:59:05 +0800 (SGT) From: Patrick Dung <patrick_dkt@yahoo.com.hk> To: freebsd hackers <freebsd-hackers@freebsd.org> Subject: Strange write speed between /file and /tmp/file (may be related to 4k advanced format) Message-ID: <1382716745.90609.YahooMailNeo@web193506.mail.sg3.yahoo.com>
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Hi ,=0A=0AI have asked the question in freebsd-questions but can't get repl= y so I tried to ask here first before submitting a bug report.=0A=0A=0AI ha= ve a FreeBSD 9.2 64 bit installed in a VM.=0AThe host is Windows 7 with vmw= are workstation, the host is using an advanced format (4k) harddisk.=0A=0A= =0AI have noticed there is strange write speed between /file and /tmp/file.= =0A/dev/da0p3 is UFS2 created by default installer.=0A=0AI am thinking if t= he problem is caused by disk alignment.=0Ada0p3 starting sector is 786594, = which seems not aligned by 4k (786594 *512/4096=3D98324.25)=0AThe dd result= is repeatable.=0A=0A=0A[root@testing2 /]# df -P=0AFilesystem=0A 512-blocks= =A0=A0=A0=A0=A0 Used=A0=A0=A0=A0 Avail Capacity=A0 Mounted=0A on=0A/dev/da0= p3=A0=A0=A0 6518712=A0=A0 4621000=A0=A0 1376216=A0=A0=A0 77%=A0=A0=A0 /=0Ad= evfs=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 2=A0=A0=A0=A0=A0=A0=A0=A0 2= =A0=A0=A0=A0=A0=A0=A0=A0 0=A0=A0 100%=A0=A0=A0 /dev=0Afdescfs=A0=A0=A0=A0= =A0=A0=A0=A0=A0=A0=A0=A0 2=A0=A0=A0=A0=A0=A0=A0=A0 2=A0=A0=A0=A0=A0=A0=A0= =A0 0=A0=A0 100%=A0=A0=A0 /dev/fd=0Aprocfs=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0=A0 8=A0=A0=A0=A0=A0=A0=A0=A0 8=A0=A0=A0=A0=A0=A0=A0=A0 0=A0=A0 100%=A0= =A0=A0 /proc=0Ahost:hgfs=A0=A0 591368064 405571456 185796608=A0=A0=A0 69%= =A0=A0=A0 /mnt-hgfs=0A[root@testing2 /]# gpart show=0A da0=0A=3D>=A0=A0=A0= =A0 34=A0 7548861=A0 da0=A0 GPT=A0 (3.6G)=0A=A0=A0=A0=A0=A0=A0 34=A0=A0=A0= =A0=A0 128=A0=A0=A0 1=A0 freebsd-boot=A0 (64k)=0A=A0=A0=A0=A0=A0 162=A0=A0 = 786432=A0=A0=A0 2=A0 freebsd-swap=A0 (384M)=0A=A0=A0 786594=A0 6760448=A0= =A0=A0 3=A0 freebsd-ufs=A0 (3.2G)=0A=A0 7547042=A0=A0=A0=A0 1853=A0=A0=A0= =A0=A0=A0 - free -=A0 (926k)=0A=0A[root@testing2 /]# dd if=3D/dev/zero of= =3D/tmp/file bs=3D50M count=3D4=0A4+0 records in=0A4+0 records out=0A209715= 200 bytes transferred in 10.303288 secs (20354202 bytes/sec)=0A[root@testin= g2 /]# rm /tmp/file=0A[root@testing2 /]# dd if=3D/dev/zero of=3D/tmp/file b= s=3D50M count=3D4=0A4+0 records in=0A4+0 records out=0A209715200 bytes tran= sferred in 9.789672 secs (21422087 bytes/sec)=0A[root@testing2 /]# rm /tmp/= file=0A[root@testing2 /]#=0A ~^C=0A[root@testing2 /]# dd if=3D/dev/zero of= =3D/file bs=3D50M count=3D4=0A4+0 records in=0A4+0 records out=0A209715200 = bytes transferred in 6.826694 secs (30719877 bytes/sec)=0A[root@testing2 /]= # rm /file=0A[root@testing2 /]# dd if=3D/dev/zero of=3D/file bs=3D50M count= =3D4=0A4+0 records in=0A4+0 records out=0A209715200 bytes transferred in 6.= 955417 secs (30151348 bytes/sec)=0A[root@testing2 /]# rm /file=0A=0AThanks = and regards,Patrick Dung
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