Slow after many files transfered? 5.0b14

[krisha]

I'm copying some files to my new unraid, in generally this is 200 GB splitted into ~500k files.

At startup it was copying mostly small files, with a rate of ~30 MB/s (which is slow already but acceptable). After some hours it dropped to less than 8 MB/s. Currently it's transfering files in the size of 500 MB - which do not need much seek.

 

The harddisk can be written with ~100 MB/s, Ethernet connection (Realtek 811E) is 1 GBit/s. The drive leds of origin (desktop PC) and unRaid blinks in an interval of ~2 seconds.

 

Why is this?

 

Also on 'top' I see that 3,9 GB of RAM out of 4 GB is used. CPU is idle at around 80%. Could it be that there is a memory leak? Attached a picture of 'top' sorted by memory :-)

 

 

[Joe L.]

3.9GB of memory is in use, but 3.4Gb of that is in the disk cache, and is available if needed.

 

All Linux will buffer as much as possible in available memory.  When an access to a disk is made, it is first looked for in the in-memory-disk-buffer.  If there, no need to even access the disk.

 

The least-recently-used disk block is reused when a new disk block (one not currently in the cache) is accessed.  Eventually, if not accessed again, it will again become the least-recently-used disk block.

 

Therefore, the first time you either read or write 4GB of data to your array, almost all memory will be used by the disk-buffer-cache.

It is completely normal and expected.