On 02 April, 2010 - Abdullah Al-Dahlawi sent me these 128K bytes: > Hi all > > I ran a workload that reads & writes within 10 files each file is 256M, ie, > (10 * 256M = 2.5GB total Dataset Size). > > I have set the ARC max size to 1 GB on etc/system file > > In the worse case, let us assume that the whole dataset is hot, meaning my > workingset size= 2.5GB > > My SSD flash size = 8GB and being used for L2ARC > > No slog is used in the pool > > My File system record size = 8K , meaning 2.5% of 8GB is used for L2ARC > Directory in ARC. which ultimately mean that available ARC is 1024M - 204.8M > = 819.2M Available ARC (Am I Right ?)
Seems about right. > Now the Question ... > > After running the workload for 75 minutes, I have noticed that L2ARC device > has grown to 6 GB !!!!!!! ???? No, 6GB of the area has been touched by Copy on Write, not all of it is in use anymore though. > What is in L2ARC beyond my 2.5GB Workingset ?? something else is has been > added to L2ARC !!!! [ snip lots of data ] This is your last one: > module: zfs instance: 0 > name: arcstats class: misc > c 1073741824 > c_max 1073741824 > c_min 134217728 [...] > l2_size 2632226304 > l2_write_bytes 6486009344 Roughly 6GB has been written to the device, and slightly less than 2.5GB is actually in use. > p 775528448 /Tomas -- Tomas Ögren, st...@acc.umu.se, http://www.acc.umu.se/~stric/ |- Student at Computing Science, University of Umeå `- Sysadmin at {cs,acc}.umu.se _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
