Date: Thu, 30 Sep 2004 12:28:18 +0200 From: Ivan Voras <ivoras@fer.hr> To: hackers@freebsd.org Subject: GEOM (ggate) compression consumer +problem Message-ID: <415BDFC2.1020304@fer.hr>
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I've made a GEOM compression layer daemon for ggate (compresses data before storing to underlying file/media). It's still early version and unfinished, and it's available at: http://ivoras.sharanet.org/ggcomp.tgz (caveat: don't overflow it; e.g. storing 50MB from /dev/zero onto a device backed by a 10MB file is fine (with -c5 switch), but doing the same with /dev/random is not (risk of kernel panic)) I know it supports building (and using) an UFS[2] filesystem in it, I haven't tried others (It registers as a device with 8k sectors; it seems it's the maximum UFS can handle, although the compression would be more efficient with larger sector sizes). It's really good at making backups of /dev/zero :) Now the problem: I currently only tested this on an old kernel (5.2-CURRENT from a few months ago), so this might be fixed in newer versions, but when I stress it with writing large files, the system 'hangs' with my process (ggcomp) in 'wdrain' state. I'm not doing anything extraordinary (except that compression takes time...) in it, so I don't think it's "my fault". Any ideas?
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