1 04/21/86 init_vol
2
3 Syntax as a command: init_vol volume_name drive_name -control_arg
4
5
6 Function: writes the label of a new physical volume and sets up its
7 VTOC and volume map. This operation destroys any previous contents of
8 the physical volume. This command can be used in ring 1 or ring 4. It
9 is also automatically entered when a cold boot is done to initialize
10 the RPV.
11
12
13 Arguments:
14 volume_name
15 is the name of a physical volume.
16 drive_name
17 has the form <subsys>_<nn>s,
18 where:
19 subsys is the disk subsystem name dska
20 nn is the device number. 00 to 64
21 s is the subvolume name, for MSU3380 or MSU3390 ab or c.
22 example: dska_02 or dskb_00b.
23
24
25 Control arguments:
26 -special
27 enters dialogue with the user. The -special control argument is
28 recommended for all RLV volumes.
29 -copy
30 initializes a copy of an already accepted physical volume -copy
31 also enters dialogue with the user.
32 -rlv
33 specifies that the physical volume is to be registered as part of
34 the root logical volume. this control argument can be used only
35 during a cold boot of the root physical volume at ring-1 initializer
36 command level.
37
38
39 Notes on special mode: Special mode is entered when -special is given
40 on an init_vol command line, when the rebuild_disk command is used, or
41 when a cold boot of the RPV is done. In special mode, the user may
42 specify various parameters of the volume being initialized as other
43 than their default values. Special mode uses a request loop subsystem
44 to allow entry of these parameters. This includes the ability to
45 specify the locations and extents of partitions.
46
47 Defaults for volume initialized by init_vol or rebuild_disk command are
48 no partitions and VTOC size constrained by average segment length of
49 5.0.
50
51
52 Defaults for RPV initialized by cold boot sequence are partitions laid
53 out on pack as follows.
54
55 partition partition low/high
56 name size in records end of pack
57
58 HC 2500 low
59 CONF 4 low
60 <paging region> <all space not used by partitions>
61 FILE 255 high
62 BCE 2200 high
63 LOG 256 high
64 DUMP 2000 high
65 BOS 270 high
66 ALT as needed high
67
68
69 VTOC size constrained by average segment length of 2.0
70
71 For non-RPV packs belonging to the RLV, it is recommended that special
72 mode be used to set an average segment length of 4.0 since directories,
73 which reside on the RLV, are usually smaller than other segments. A
74 smaller average segment length increases the number of VTOC entries
75 VTOCES on the pack. Since it is easier to make the VTOC bigger than
76 to make it smaller, the recommended procedure is to start with 4.0 as
77 an average segment length. If more VTOCES are needed later, the
78 rebuild_disk command can be used to define them.
79
80 When using volume backup to recover the contents of a disk pack, make
81 sure there are at least as many available records and total VTOC
82 entries as there were on the physical volume before it was damaged.
83
84
85 Notes on request loop of init_vol: The following request lines may be
86 typed when init_vol is invoked with the -special control argument,
87 when the rebuild_disk command is being used, or within the cold boot
88 sequence.
89 asl FFF.FF, avg FFF.FF
90 specifies the average segment length, which is used to determine the
91 VTOC size. As partitions are defined, the VTOC size is adjusted to
92 maintain a VTOC entry to free page ratio producing this average
93 segment length. When operating in this mode the default with
94 average segment length = 5.0, the parameters are said to be
95 constrained by average segment length.
96 default
97 causes all parameters to be reset to their cold boot defaults,
98 including the list of partitions. This request is only valid within
99 the cold boot sequence.
100
101
102 end
103 causes the command init_vol or rebuild_disk to proceed using the
104 parameters as they stand at this point.
105 help
106 lists all requests available within the init_vol request loop.
107 lace N
108 specifies physical address assignment interlace; i.e., specifies
109 that the system should try to place the pages of a segment N disk
110 records apart on the target disk. The default value for N is 2.
111 This request is only valid in the rebuild_disk command.
112
113
114 list
115 causes the current parameters to be listed, including partition
116 data, VTOC size, number of VTOC entries and effective average
117 segment length. Issuing other requests causes these parameters to
118 change. When the request loop is entered, a list request is
119 performed automatically.
120 nvtoce N
121 specifies the VTOC size by the number of VTOC entries to be created.
122 As five VTOC entries occupy each page, this number is rounded up to
123 the next five before use.
124
125
126 This constrains parameters by VTOC size.
127 part name hilow size
128 where name is a 4-character or fewer partition name, hilow is either
129 "high" or "low", and size is the partition size in records, defines
130 a partition to be allocated on the pack. The hilow argument
131 specifies which end of the pack, with respect to device address, the
132 partition shall be allocated. Successive requests for "high"
133 partitions receive successively lower addresses, and successive
134 requests for "low" partitions receive successively higher addresses.
135 Partitions may not be redefined without issuing the "startover"
136 request.
137 quit
138 causes the command init_vol or rebuild_disk to be aborted, without
139 initializing or rebuilding any disks. This request is not valid
140 within the cold boot sequence.
141
142
143 startover
144 causes all parameters to be reset to their defaults init_vol
145 command defaults not cold boot defaults. In particular, no
146 partitions are defined, even in the cold boot environment.
147 vtoc N
148 specifies the total number of pages to be allocated for the volume
149 header and volume table of contents VTOC. All other space on the
150 pack is available for paging and partitions. When the "vtoc" or
151 "nvtoce" request is given, the parameters are said to be constrained
152 by VTOC size, and average segment length varies as partitions are
153 defined.
154
155
156 Notes: The init_vol command queries the user before destroying the
157 label of any pack that appears to be a validly labeled pack. A message
158 giving the pack's physical volume name and time of last use is
159 displayed.
160
161 The init_vol command takes about 90 seconds for a model M400 disk.