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| | | |  | CAUTION: (vparcreate only) When you
specify the granularity value for only one type of memory (ILM or
CLM), the granularity value for the other type of memory is set using
the default granularity value. For example, if you specify only -g ILM:256, the -g CLM:128 is implied
where 128 is the vPars default granularity
value. If your system (or nPartition) contains
a large amount of memory (32 GB or more), you should set the granularity
value to the largest amount possible to reduce the total boot time
(relative to boot time in nPars/standalone) caused by the initial
hardware scanning of memory. For CLM on PA-RISC platforms and for
both ILM and CLM on Integrity platforms, you should choose the largest
possible granularity value. However, you should be careful when using the
granularity option; using the option incorrectly can cause all the
virtual partitions to not be bootable. Further, granularity in the vPars database can
only be specified during the creation of the vPars database. This
means the first vparcreate command performed to
create the database can be used to specify the granularity, but it
cannot be changed after that. It cannot be changed by subsequent vparcreate commands nor any other commands; any change
in values requires the entire vPars database to be re-created. Therefore,
read this section thoroughly. For details on granularity values and granularity
limitations, see the vparresources(5) manpage. The granularity section
of this manpage is provided below since there are critical notes in
the manpage of which you should know when planning a granularity value.
These include: The minimum value for granularity of both ILM and
CLM is 64 MB. The chosen granularity value(s) must be an integral
power of 2 (in other words, 2^X). (Integrity only) There is a limit on the number of
CLM granules per cell and total ILM granules you can set. Use the vparenv command to see the maximum possible granules for
ILM and CLM for your specific system. For example: # vparenv
vparenv: The next boot mode setting is "vPars".
vparenv: The ILM granule size setting is 128.
vparenv: The CLM granule size setting is 128.
vparenv: Note: Any changes in the above settings will become effective
only after the next system reboot.
vparenv: Note: The maximum possible CLM granules per cell is 64.
vparenv: Note: The maximum possible ILM granules for this system is 1024.
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If either of these values are exceeded
when you set your granularity values, the vPars Monitor will not boot
any virtual partitions. You must rebuild your vPars database such
that the number of granules related to both ILM and CLM do not exceed
the numbers in your vparenv output. (PA-RISC only) Excluding the first granule, a portion
of which is used by the vPars Monitor, there must be at least one
entire granule that exists below the 2 GB limit for each virtual partition.
These granules below the 2 GB limit are used by kernel of each virtual
partition. Especially for nPartitions or systems containing 32
GB or more of total memory, you should set the granule to the highest
possible granule size to reduce the time in scanning the memory during
the initial hardware boot. (Integrity only) In order for the virtual partitions
in an active database to be able to boot, the granularity values in
the vPars database must match those written in the system firmware.
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Granularity described in vparresources(5) | |
For reference, below is the granularity section
of the manpage vparresources(5): |
Granularity
Memory is normally assigned to vPars in units called granules.
Exceptions are described below. The granule values for CLM and ILM
can be different. However, both are subject to the following rules:
+ MOST IMPORTANT, READ CAREFULLY. Granularity, the value of a
granule specification, is not a resource. Resource assignments can
be modified, even if some resource modifications require that a
vPar be Down. Granularity can only be specified when creating a
new database. It cannot be changed thereafter.
+ The minimum values (ILM and CLM) are 64 MB.
+ The default values are 128 MB.
+ The recommended specifications are described below.
+ Any chosen granularity must be an integral power of 2, not just a
multiple of 64. For example, 256 is a legal value, but 192 is not.
+ Although a granularity must be an integral power of 2, memory can
be assigned in any multiple of that value. For example, if the CLM
granularity is 128 MB, it is legal to assign 384 MB of CLM to a
vPar.
+ Integrity systems have a platform-dependent limit to the
number of CLM granules per cell or ILM granules that may be
configured. You can determine specific limits for your
installation by using the vparenv command and examining the "The
maximum possible xLM granules..." messages. Note: When in nPar
mode, the vparenv command does not display the "The maximum
possible xLM granules..." messages if the next boot mode setting is
nPars. So in order to get these values, you have to first change
the next boot mode setting to vPars (reboot not required) and then
invoke the vparenv command. These values, combined with your total
memory of each type, determine the minimum granularities you should
specify in order to allow your vPars to boot. For example, if you
are allowed 1024 ILM granules and your total memory is <= 128 GB,
you can use the default ILM granularity of 128 MB. Or if you are
allowed 16 CLM granules per cell, and your nPar configuration
includes two cells each configured with 8 GB of CLM, your CLM
granularity must be >= 512 MB.
If the total ILM memory or CLM memory per cell exceeds that which
can be configured in the maximum number of granules using your
specified granularity, the vPar Monitor will not boot any vPar. In
this case, you must increase one or both granularities
appropriately so that all available memory can be accommodated.
This will require a complete reconfiguration of your database.
Careful configuration planning will avoid this situation.
Granularity limitations do not apply to PA-RISC platforms.
However, there are guidelines that do apply to both PA-RISC and
Integrity systems. These are described next.
+ Recommendations for ILM and CLM granularity specifications:
On PA-RISC platforms, each vPar needs ILM below 2 GB to load and
launch its kernel. However, portions of the first granule
(starting at address 0) are used for the Monitor's code and data,
therefore will not be used for the kernel. Hence, excluding the
first granule, there should be at least one granule below 2 GB for
each partition. So if ILM granularity is 128 MB, the first 2 GB
will consist of 16 granules. Therefore, it will be possible
to load and launch the maximum supported 8 vPars. If ILM
granularity is 256 MB, there are only 8 granules in the first 2 GB.
The Monitor uses portions of the first one. So it will only be
possible to load and launch 7 or fewer vPars. On ab Integrity
server, there is no similar constraint on the maximum ILM
granularity.
For CLM on PA-RISC platforms, and for both ILM and CLM on
Integrity systems, Hewlett-Packard recommends choosing the
largest possible granularity for performance reasons. The
granularity can be such that it is equal to the partition with the
least amount of that memory type. For example, if the system
contains 64 GB of ILM and the smallest ILM specification of any
vPar is 1 GB, then ILM granularity can be 1 GB. If the system
contains 64 GB of CLM per cell and the smallest CLM specification
from any cell of any vPar is 4 GB, the CLM granularity can be 4 GB.
+ For an Integrity server, the chosen granularity values must
also be written to system firmware storage. When the Monitor is
started and a vPar database is loaded, the values in the database
must match those in firmware, or the Monitor will not allow the
database to be used.
While in nPars mode, you should use the vparstatus and vparenv
commands to verify that the database and firmware granularities are
identical. If not, you must either create a new database with the
correct granularities using the vparcreate -g command, or change
the firmware granularities with the vparenv -g command.
Although memory is normally allocated in integral granules, some
memory ranges are withheld for use by the Monitor or by firmware. The
vparstatus -m command displays these ranges. Other ranges of address
space are simply non-existent. Because of this fragmentation, the
Monitor may assign your vPar slightly more or less than an integral
granule of memory when the vPar boots. |
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