Hi, I had configure squid2.6 with this parameter ./configure \ --prefix=/usr/local/squid_coss \ --enable-coss-aio-ops \ --with-pthreads \ --with-aio \ --with-coss-membuf-size=33554432 \ --enable-linux-netfilter \ --enable-large-cache-files \ --with-large-files \ --enable-async-io=256 \ --enable-snmp \ --enable-cache-digests \ --enable-follow-x-forwarded-for \ --enable-storeio="aufs,coss" \ --enable-removal-policies="heap,lru" \ --with-maxfd=65536 \ --enable-epoll \ --disable-ident-lookups And my squid.conf of COSS as cache_dir coss /dev/cciss/c0d5 100000 max-size=33554431 overwrite-percent=40 And use command squid -z I got this error FATAL: COSS cache_dir size exceeds largest offset I try to random the max size and the size can't more than 7500. What's happen ? How I can use the maximum disk for single partition. Thanks Sunin.T