By default, /etc/grio_disks contains the parameters for disks supported by Silicon Graphics for optimal I/O sizes of 64K, 128K, 256K, and 512K. Table 9-4 lists these disks. Table 9-5 shows the optimal I/O sizes and the number of optimal I/O size requests each of the disks listed in Table 9-4 can handle in one second.
| Optimal I/O Size | Number of Requests per Second |
|---|---|
| 65536 | 23 |
| 131072 | 16 |
| 262144 | 9 |
| 524288 | 5 |
To add other disks or to specify a different optimal I/O size, you must add information to the /etc/grio_disks file. If you modify /etc/grio_disks, you must rerun the cfg command to re-create /etc/grio_config and then restart the ggd daemon for the changes to take effect (see the section "Restarting the ggd Daemon" in this chapter).
The records in /etc/grio_disks are in these two forms:
ADD "disk id string" optimal_iosize number_optio_per_second SETSIZE device optal_iosizeIf the first field is the keyword ADD, the next field is a 28-character string that is the drive manufacturer's disk ID string. The next field is an integer denoting the optimal I/O size of the device in bytes. The last field is an integer denoting the number of optimal I/O size requests that the disk can satisfy in one second.
Some examples of these records are:
ADD "SGI SEAGATE ST31200N9278" 64K 23 ADD "SGI 0064N1D 4I4I" 50K 25If the first field is the keyword SETSIZE, the next field is the pathname of a disk device. The third field is an integer denoting the optimal I/O size to be used on the device.
Normally, the optimal I/O size of a disk device is determined by its stripe unit size. If the disk is not striped or you do not want to use the stripe unit size for the optimal I/O size, you can use the SETSIZE command to tell the cfg command how to construct the lines for the GRIO disk in the /etc/grio_config file.
An example of a SETSIZE record is:
SETSIZE /dev/rdsk/dks136d1s0 50K