Per my prior e-mails and offering ... Based on reading through the current [1] and Wiki [2] developments, I have the following recommendation.
- Create a new, separate Objective in Section 204 - Suggested "Section 204.4 Device Mapper" follows [A] - From other 204 Sections ... - Remove Device Mapper (e.g., /dev/mapper) - Remove WWID/WWN and SCSI ID (e.g., scsi_id) - NOTE: Do not remove iSCSI** (although may belong in another section) -- bjs **NOTE: Given the details involved with iSCSI initiator (client), among other options, consider moving iSCSI initator (plus any other "network storage client" boot/config/init) to its own, separate Section 204 (204.5?). This e-mail only covers Device Mapper and its facilities, which I suggest for Section 204.4. [1] http://www.lpi.org/linux-certifications/programs/lpic-2/exam-201/#section-203 [2] http://wiki.lpi.org/wiki/LPIC-2_Objectives#Topic_203:_Filesystem_and_Devices [A] Objective "Suggestion" w/extra detail (beyond what would be published) Objective 204.4 Device Mapper Weight: 1 (as 204.2 Today) or 2 (as 204.2 Wiki/Future) NOTE: 1-2 is _less_ than other 204 Sections Description: Candidates should be able to use DeviceMapper facilities and userspace to identify, filter, blacklist, whitelist and resolve presentation of block devices, including for virtualization guests, LVM mappings, multitarget mappings (SCSI/SAS) and multipath mappings (FC/SAN). NOTE: This section is _not_ for things done with udev, but _only_ DeviceMapper-specific facilities and userspace. - Command: dmsetup E.g., dmsetup [info|ls] - Command: scsi_id E.g., scsi_id --page=0x8[0|3] --device=(device) - Path(s): /dev/disk/by-[id|label|path|uuid]/ These should be self-explanatory ;) - Path(s): /dev/mapper/ Moved from LVM Section, which is more for LVM operations - Path(s): /sys/block/ Block device paths -- e.g., often symlinks to /sys/devices - Path(s): /sys/devices/ Device bus/host/lun paths -- e.g., Bus/HBA as well as c:t:d:s - Config*: lvm.conf Limited to: volume_list, filter, issue_discards - Config*: multipath.conf Limited to: wwid and alias only - Runtime: /var/lib/multipath/bindings Limited to: wwid-only *lvm.conf _limited_ to: - Section "activation" (VG/LV activation options) - Option "volume_list" (VG implicit whitelist) - Section "device" (PV/device options) - Option "filter" (device blacklist and/or whitelist) - Option "issue_discards" (NAND EEPROM SSD lifespan/perf) - Option "preferred_names" (path order of preference) LVM NOTE: Remember, "volume_list" and/or "filter" is often used to ensure virtualization hosts do _not_ access Physical Volumes (and active Volume Groups) for their virtualization guests. *multipath.conf _limited_ to: - Section "blacklist" (blacklist) - Option "wwid" (blacklist) - Section "multipaths / multipath" (whitelist/alias in stanza) - Option "wwid" (whitelist) - Option "alias" (label) LVM NOTE: It's also important to "filter" Devices so they are only found on select devices for multitarget (SCSI/SAS) and multipath (FC/SAN). -- Bryan J Smith - Professional, Technical Annoyance b.j.smith at ieee.org - http://www.linkedin.com/in/bjsmith
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