tag:blogger.com,1999:blog-4991582231121311353.post205278024194222239..comments2024-01-23T17:43:12.624+11:00Comments on Virtual Nomad: StarWind Virtual SAN review - Part 3 - Disk and Cache typesvmnomadhttp://www.blogger.com/profile/02515151385546400290noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-4991582231121311353.post-45196065548912264062024-01-07T04:59:58.468+11:002024-01-07T04:59:58.468+11:00Thanks, great post. Thanks, great post. Serpenscandidahttps://serpenscandida.tumblr.com/noreply@blogger.comtag:blogger.com,1999:blog-4991582231121311353.post-90735094582405757422016-07-08T10:41:13.287+10:002016-07-08T10:41:13.287+10:00Hi Patrick,
That's the nature of LSFS as it d...Hi Patrick,<br /><br />That's the nature of LSFS as it doesn't overwrite data, but instead writes data to new log and invalidates old blocks. <br /><br />Imagine creating a file that consists of blocks A,B,C. All of them are written sequentially into the log-1. When block B is changed LSFS writes new block B to the new log-2 file and updates the pointer for block B to log-2 file. Later on, block C is updated and it ends in log-3, and again the pointer is updated with new location of block C and the old block C in log-1 is invalidated and will be cleaned up during the garbage collection process. <br /><br />Also, garbage collection process will move block A to the new log file and will delete block B and C from log-1 file. So, you sequentially written file turns to randomly spread chunks of data across the LSFS logs.<br /><br />Therefore, when you retrieve the file you get a number of random Reads as you read the file from different LSFS log files. <br /><br />LSFS eliminates the Write penalty and that's one of the heave hitters on the storage. But you have mostly Read pattern on the storage you may want to consider using Flat storage instead. <br />vmnomadhttps://www.blogger.com/profile/02515151385546400290noreply@blogger.comtag:blogger.com,1999:blog-4991582231121311353.post-7990429360078299152016-07-08T01:30:57.554+10:002016-07-08T01:30:57.554+10:00Thanks for this awesome post!
I have a question.
...Thanks for this awesome post!<br /><br />I have a question.<br /><br />Why does LSFS turn sequential Reads into Random reads? Does this make any sense?<br /><br />I thought the main reason for LSFS is to turn random IOs into sequential IOs to improve performance?<br /><br />Best Regards<br />PatrickPatrickhttps://www.blogger.com/profile/09280488603063038527noreply@blogger.com