The average clickhouse-server write size is approximately 1 MB (1024 KB), and thus the recommended stripe size is also 1 MB. When using RAID-5, RAID-6 or RAID-50, always increase stripe_cache_size, since the default value is usually not the best choice.Ĭalculate the exact number from the number of devices and the block size, using the formula: 2 * num_devices * chunk_size_in_bytes / 4096.Ī block size of 64 KB is sufficient for most RAID configurations. If you have more than 4 disks, use RAID-6 (preferred) or RAID-50, instead of RAID-5. In using LVM, there is nothing against using it. (selecting wrong chunk size misalignment of chunks choosing a wrong raid type forgetting to cleanup disks). LVM by itself (without RAID or mdadm) is ok, but making RAID with it or combining it with mdadm is a less explored option, and there will be more chances for mistakes When creating RAID-10, select the far layout. When using HDD, you can combine their RAID-10, RAID-5, RAID-6 or RAID-50.įor Linux, software RAID is better (with mdadm). Give preference to a lot of servers with local hard drives over a smaller number of servers with attached disk shelves.īut for storing archives with rare queries, shelves will work. If your budget allows you to use SSD, use SSD. You can use ClickHouse in a system with a small amount of RAM, even with 2 GB of RAM, but it requires additional tuning and can ingest at a low rate. The recommended amount of RAM is 32 GB or more. If your system has less than 16 GB of RAM, you may experience various memory exceptions because default settings do not match this amount of memory.
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