1. Sys Admin Course Physical Storage and File Systems Fourie Joubert

2. Sys Admin Course Physical Storage Physical disks may be inside the server, or in an external enclosure The server may also be connected to storage in other ways, such as on a network

3. Sys Admin Course The physical disks may have platters, or be SSD

4. Sys Admin Course The disks may have different speeds Seeks times vary from around 4ms to 15 ms Latencies:

5. Sys Admin Course There are different types of disk interfaces – IDE (deprecated) – SCSI (mostly deprecated) – SATA – SAS – FC

6. Sys Admin Course Interface speeds – Vary from around 1Gbps to around 6Gbps

7. Sys Admin Course Connections to external disk enclosures – SAS – iSCSI – FC

8. Sys Admin Course Physical storage devices in Linux – /dev/sda – /dev/sdb – /dev/sdc Partitions on the disks – /dev/sda1 – /dev/sda2 – …

9. Sys Admin Course RAID – Redundant Array of Independent Disks RAID levels – RAID 0: Striping – RAID 1: Mirroring – RAID 2: Bit-level striping with dedicated Hamming- code parity – RAID 3: Byte level striping with dedicated parity – RAID 4: Block level striping with dedicated parity – RAID 5: Block level striping with distributed parity – RAID 6: Block level striping with double distributed parity

10. Sys Admin Course Nested RAID – RAID 0 + 1: creates a second striped set to mirror a primary striped set – RAID 1 + 0: creates a striped set from a series of mirrored drives

11. Sys Admin Course Hardware vs software RAID – Hardware RAID: the interface card has a dedicated setup system Software RAID – Managed by the operating system – mdraid (preferred) – dmraid (user space)

12. Sys Admin Course Working with the partition table parted parted /dev/sda > print

13. Sys Admin Course > mklabel type > mklabel gpt > mkpart part-type fs-type start end > rm number > toggle number flag

14. Sys Admin Course gparted

15. Sys Admin Course Filesystems ext2 (old) ext3 (old-ish) fat16 (old win) fat32 (old win) hfs (apple) jfs (IBM journalled) linux-swap (swap) ntfs (win) reiserfs (old-ish) hp-ufs (HP) sun-ufs (Sun) xfs (Silicon Graphics) btrfs(btree)

16. Sys Admin Course mkfs – create a file system mkfs –t ext4 /dev/sda3 e2label – label an e-filesystem e2label /dev/sda3 /work

17. Sys Admin Course The file system table blkid –o list You will get a list of your block devices, with their /devs, labels, mount points and UUIDs

18. Sys Admin Course Looking at the fstab less /etc/fstab 1: column is the mount id 2: mount point (directory) 3: fs type 4: additional options 5: dump options 6: filesystem check order

19. Sys Admin Course Mounting a device manually mount /dev/sda1 or mount /home

20. Sys Admin Course Allowing users to do mounts FUSE: Filesystem in user space

21. Sys Admin Course Checking a filesystem umount /home fsck.ext4 /dev/sda2 fsck.ext4 –y /dev/sda2 Checking a filesystem Repairing a filesystem fsck –p /dev/sda2

22. Sys Admin Course GUI Mode filesystem operations Applications -> System Tools -> Disk Utility

23. Sys Admin Course More complex configurations Cluster file systems Aggregate many devices under a single name space

24. Sys Admin Course