Emerson ATCA-S201 manual #Wthreads value

RTM-ATCA-SXXX Overview

Note: The <value> should be set to multiples of PAGE_SIZE. The maximum supported value is 64 * 4096 = 262144.

#FirstBurstLength <value>

Default: 65536, Sets the maximum amount of unsolicited data the initiator may transmit in the first burst of a transfer either with and/or right after the iSCSI command. Used together with InitialR2T and ImmediateData.

Note: The <value> should be set to multiples of PAGE_SIZE. The maximum supported value is 16 * 4096 = 65536.

#DefaultTime2Wait<value>

Not currently supported #DefaultTime2Retain <value> Not currently supported #MaxOutstandingR2T <value>

Default: 1, Controls the maximum number of data transfers the target may request at once, each of up to MaxBurstLength bytes.

#DataPDUInOrder <YesNo>

"Yes" — default:, Indicates the initiator MUST send data PDUs within sequences have to be at continuously increasing addresses.

“No” — Not supported. #DataSequenceInOrder <YesNo>

"Yes" — default: Indicates the initiator MUST send Data Sequences with continuous non-decreasing sequence offsets (R2T buffer offset for writes, or the smallest SCSI Data-In buffer offset within a read data sequence). “No” — Not supported.

#ErrorRecoveryLevel 0

Default 0, Establishes the recovery level supported by the target. #HeaderDigest <CRC32CNone>

"None" — default. CRC not enabled.

"CRC32C" — Indicates Target will support CRC32C checksum to protect iSCSI PDU’s headers, if requested by initiator.

Notes: (1) header digests are not used during discovery sessions. (2) CRC32C may negatively affect overall target performance.

#DataDigest <CRC32CNone>

"None" — default. CRC not enabled.

"CRC32C" — Indicates Target will support CRC32C checksum to protect iSCSI PDU’s data segments, if requested by initiator.

Notes: (1) data digests are not used during discovery sessions. (2) CRC32C may negatively affect overall target performance.

#Wthreads <value>

Default: 8

Sets the number of threads used to perform the block I/O to the blades’ disk resources. 8 threads was determined optimal for the majority of deployments and workloads.

Lun <number> Path=<device>,Type<blockio>,ScsiID=<unique-identifier>

defines a mapping between a Logical Unit Number <number> and a block device <device>. <number>: The value between 0 and 2^14-1

<device>: Linux device path mapped to the LUN

<blockio> Indicates the blade will perform direct block i/o with the device, bypassing page-cache for all operations. Optimal for non-aligned sector transfers large block transfers.

<unique-identifier>a unique ID assigned to the iSCSI volume. It is required to assist mulitipath-aware initiator host accessing the same <device> through several targets. The <unique-identifier> must not exceed 16 characters.

6806800H62B ATCA‐S201 Installation and Use Guide 87