Is it possible ot determine MB/sec transfer rate of a drive/partition?

[gwichman]

I have a RAID10 partition that'd getting hammered. It'd be useful to see what kind of throughput we're getting out of it in terms of MB/sec read and written. Whats the easiest way to determine this?

thanks!

 

[Norwich]

the hdparm command - though designed for optimising IDE disks - will report transfer rates on scsi drives.

Try:

hdparm -t /dev/sda


etc.

 

[gwichman]

that seems to be more for what a drive/device is *capable* of.. i.e. it says to run it on an inactive system. I'm talking about a system that is currently active and experiencing a lot of disk reads/writes..

iostat can show me the number of blocks written and read per second, however the man page for iostat says that blocksize is of an indeterminate size so theres no way to correlate # of blocks to MB. If there was that'd be a great way to check..

 

[Morsing]

512 bytes per block.

Unfortunately there are no really good tools for Linux to do performance measuring and finding bottlenecks.

Cheers Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support

 

[gwichman]

if it's 512bytes per block, why does the man page say it's of an indeterminate size?

 

[Morsing]

That depends on what kind of blocks it's looking for. Harddisks have 512 byte blocks (sectors) but the OS can put them in logical blocks. For ext2/ext3 this is 1024 bytes (up to 4k but you have to set this yourself). Reiserfs is 4k.

What kind of file system is it?? Try 'debugfs' on it to get the block size.

Cheers Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support

 

[gwichman]

we use a variety of file systems.. reierfs mostly i'd say. Some ext2/ext3..

debugfs only seems to apply to ext2 file systems looking at the man page.