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Sun QFS and Sun Storage Archive Manager 5.3 Reference Manual Sun QFS and Sun Storage Archive Manager 5.3 Information Library |
1. User Commands (Man Pages Section 1)
2. Maintenance Commands (Man Pages Section 1M)
3. Library Functions (Man Pages Section 3)
4. Library Functions (Man Pages Section 3X)
5. File Formats (Man Pages Section 4)
NAME dvt - sequentially write and read a file. SYNOPSIS dvt [-c block_count] [-C] [-d] [-e error_limit] [-g stripe_group] [-o rw|w|r] [-O byte_offset] [-p] [-P a|f|o|0(zero)] [-q queue_size] [-R read_threads] [-s block_size] [-v] [-W write_threads] filename AVAILABILITY SUNWsamtp DESCRIPTION dvt writes to a disk file and then reads the disk file. The time required for the transfer(s) is measured, and the read and write transfer rates are computed. The read optionally verifies the written data. OPTIONS -c block_count The number of blocks to be written/read. -C Specifies that I/O should be buffered through the page cache. -d Specifies direct I/O: I/O should not use the page cache. -e error_limit Specifies the maximum number of data miscompares allowed to occur before the test is stopped. -g stripe_group Specifies the number of the striped group where the file is to be preallocated. Stripe_group is a number 0..127 corresponding to a set of gXXX devices in the SAM-QFS master configuration file. This option applies only to filesystems configured with stripe groups. -i stride Set the I/O offset stride to stride. -o rw|w|r The option rw means write the file and then read the file. This is the default. The option w means write the file. The option r means read an existing file written by dvt. -O byte_offset Offset initial file I/O by byte_offset bytes. -p Specifies the file should be preallocated. This option applies only to SAM-QFS filesystems. -P a|f|o|0 The data pattern. a is an ascending pattern which uses the 64 bit byte offset as the pattern. f is an ascend- ing pattern which uses the 64 bit byte offset as the pattern, plus inserts 16 characters of the filename at 8K boundaries. o writes all 1's. 0 (the numeral zero) writes all 0's. -q queue_size Specifies the number of the entries that will be out- standing in the work queue. The queue_size should be larger than read_threads. -R read_threads Specifies the number of the threads that will be out- standing for read. If read_threads is less than write_threads, write_threads will be used. -s size The block size in bytes. If the size has the suffix k, the block size is in units of kilobytes. The size must be at least 1064 bytes to hold the parameter block header. -v Data will be verified on the read pass. The times and transfer rates will include this comparison time. -W write_threads Specifies the number of the threads that will be out- standing for write. SEE ALSO pdvt(1) sam_advise(3), sam_setfa(3) mcf(4)