On Saturday 09 August 2003 01.20, Adam Aube wrote: > How can RAID0 have worse performance than RAID5? RAID0 was > designed to optimize disk write performance by striping writes > across multiple disks.
Because it does not add any redundancy or performance to a Squid setup. RAID0 only adds drawbacks compared to separate drives. > I would think that RAID0 would at least outperform RAID1. One cache_dir per drive gives maximal performance and flexibility for Squid but no automatic fault management. If you complement this with some software which removes the cache_dir from squid.conf and restarts Squid if a drive should fail then you do get quite acceptable level of fault recovery however. RAID0 is on performance level close to using one cache_dir per drive, but has the drawback that if one drive fails the whole RAID0 set of drives is gone. RAID1 adds redundancy, but nearly doubles the number of drives needed for the same performance compared to separate drives. RAID5 is slower than RAID1 for Squid, but if you don't really need the speed but you mus have redundancy then it may be acceptable. However, given the low price of harddrives there is barely no motivation to use RAID5 instead of RAID1 for Squid. My recommended base setup is a RAID1 setup for OS + logs, then separate drives for as many cache directories you need. For low-end setups the RAID1 set may also be used for cache. On high-end setups using RAID1 for the cache drives is recommended method of increasing the reliability and decreasing management cost at only the cost of doubles number of drives needed for cache. -- Donations welcome if you consider my Free Squid support helpful. https://www.paypal.com/xclick/business=hno%40squid-cache.org If you need commercial Squid support or cost effective Squid or firewall appliances please refer to MARA Systems AB, Sweden http://www.marasystems.com/, [EMAIL PROTECTED]
