Acer Altos easyStore M2 User Manual - Page 254

232 8 Configuring the storage system Configuring the hard disk drive The storage system supports up to four 3.5-inch hot-swappable SATA hard disk drives (HDDs). Disk configurations The storage system supports various types of disk configurations, including RAID (redundant array of independent disks), a disk subsystem that can increase performance, provide data protection, or both. • Linear - A linear configuration is similar to using multiple HDDs in a regular computer. Each HDD is an independent entity, and the data on it is self-contained. You can add or remove the HDDs without affecting the other HDDs. All the available disk space is used for data. If your storage system has only one HDD, you must use a linear configuration. However, you can use a linear configuration for two, three, or four HDDs as well. • RAID 0 - Instead of writing all the data to one HDD in a linear fashion, some bytes are written to one HDD, and other bytes are written to another. Performance is faster because reading and writing activities can occur on multiple HDDs simultaneously. All the available disk space is used for data. For RAID 0, your storage system must have at least two HDDs. However, you can use RAID 0 with three or four HDDs as well, and the HDDs can be any size. • RAID 1 - In this configuration, all the data written to one HDD is duplicated on the other HDD. This offers greater data protection since if one HDD fails, all your data is still intact on the other HDD. However, using RAID 1 means only half your available disk space is used for data; the other half is used for a duplicate (mirror) of that data. You can use RAID 1 only if your storage system has only two HDDs. If the HDDs are not the same size, the smaller of the two HDDs is used for data, and the larger of the two HDDs is used as the mirror. If one HDD fails, the other HDD continues to make its data available.