AFAIk this is still roughly correct
http://thelastpickle.com/2011/04/28/Forces-of-Write-and-Read/
It includes information on the page size read from disk.
Cheers
-
Aaron Morton
Freelance Cassandra Developer
New Zealand
@aaronmorton
http://www.thelastpickle.com
On 22/02/2013,
Hi,
On Feb 21, 2013, at 7:52 , Kanwar Sangha wrote:
> Hi – Can someone explain the worst case IOPS for a read ? No key cache, No
> row cache, sampling rate say 512.
>
> 1) Bloom filter will be checked to see existence of key (In RAM)
> 2) Index filer sample (IN RAM) will be checked
...@scode.org [mailto:sc...@scode.org] On Behalf Of Peter Schuller
Sent: 21 February 2013 00:05
To: user@cassandra.apache.org
Subject: Re: Read IO
> Is this correct ?
Yes, at least under optimal conditions and assuming a reasonably sized row.
Things like read-ahead (at the kernel level) will play i
> Is this correct ?
Yes, at least under optimal conditions and assuming a reasonably sized
row. Things like read-ahead (at the kernel level) will play into it;
and if your read (even if assumed to be small) straddles two pages you
might or might not take another read depending on your kernel setti
Hi - Can someone explain the worst case IOPS for a read ? No key cache, No row
cache, sampling rate say 512.
1) Bloom filter will be checked to see existence of key (In RAM)
2) Index filer sample (IN RAM) will be checked to find approx. location in
index file on disk
3) 1 IOPS
