Date: Sun, 11 Aug 2013 16:21:55 +0400 (MSK) From: Dmitry Sivachenko <trtrmitya@gmail.com> To: FreeBSD-gnats-submit@freebsd.org Subject: kern/181226: Writes to almost full FS eat 100% CPU and speed drops below 1MB/sec Message-ID: <201308111221.r7BCLteq003011@agata.yandex.ru> Resent-Message-ID: <201308111230.r7BCU132096706@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 181226 >Category: kern >Synopsis: Writes to almost full FS eat 100% CPU and speed drops below 1MB/sec >Confidential: no >Severity: serious >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sun Aug 11 12:30:01 UTC 2013 >Closed-Date: >Last-Modified: >Originator: Dmitry Sivachenko >Release: FreeBSD 9.2-BETA2 amd64 >Organization: >Environment: System: FreeBSD agata.yandex.ru 9.2-BETA2 FreeBSD 9.2-BETA2 #2 r253884M: Sun Aug 11 12:12:37 MSK 2013 mitya@agata.yandex.ru:/usr/obj/opt/WRK/src/sys/CAVIA amd64 FreeBSD-9.2-BETA2 >Description: I have 25TB Dell PERC 6 RAID5 array. When it becomes almost full (10-20GB free), processes which write data to it start eating 100% CPU and write speed drops below 1MB/sec (normally to gives 400MB/sec). 1889 mitya 1 100 0 2058M 1027M CPU12 12 0:47 92.77% dd systat -vm shows disk array is not busy: Disks mfid0 KB/t 63.71 tps 65 MB/s 0.77 %busy 3 If I delete some files to free space during that slow write, the same process starts writing with normal speed. I was running that machine with ~1 year old 9-STABLE without any problems. That array often overflows, and I always got "filesystem is full" error without write speed reduction. The probles appeared after I upgraded to 9.2-BETA2 few days ago. tunefs: POSIX.1e ACLs: (-a) disabled tunefs: NFSv4 ACLs: (-N) disabled tunefs: MAC multilabel: (-l) disabled tunefs: soft updates: (-n) enabled tunefs: soft update journaling: (-j) disabled tunefs: gjournal: (-J) disabled tunefs: trim: (-t) disabled tunefs: maximum blocks per file in a cylinder group: (-e) 4096 tunefs: average file size: (-f) 16384 tunefs: average number of files in a directory: (-s) 64 tunefs: minimum percentage of free space: (-m) 1% tunefs: space to hold for metadata blocks: (-k) 0 tunefs: optimization preference: (-o) space tunefs: volume label: (-L) >How-To-Repeat: >Fix: >Release-Note: >Audit-Trail: >Unformatted:
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201308111221.r7BCLteq003011>