Logical device types

Open-Systems Host Attachment Guide

Version
9.8.7
Audience
anonymous
Part Number
MK-90RD7037-31

The following table describes the types of logical devices (LDEVs) on the RAID storage systems that can be configured and used by open-systems hosts. The LDEVs on the storage systems are defined to the host as SCSI disk devices, even though the interface is Fibre Channel or iSCSI and the devices are disk drives or flash drives. For information about configuring LDEVs other than OPEN-V, contact customer support.

Device type Description
OPEN-V devices SCSI disk devices (Virtual LUN-based volumes) that do not have a predefined size.
OPEN-x devices SCSI disk devices of predefined sizes:
  • OPEN-3 (2.3 GB)
  • OPEN-8 (6.8 GB)
  • OPEN-9 (6.9 GB)
  • OPEN-E (13.5 GB)
  • OPEN-L (33 GB)

For information about the use of these devices, contact customer support.

VLL devices

(OPEN-x VLL)

Custom-size LUs that are configured by "slicing" a single fixed-size LU into two or more smaller LUs to improve host access to frequently used files. VLL devices are configured using the Virtual LVI/LUN (VLL) feature. The product name for OPEN-x VLL devices is OPEN-x-CVS, in which CVS stands for custom volume size. OPEN-L devices do not support VLL.

LUSE devices

(OPEN-x*n)

Combined LUs composed of multiple OPEN-x devices. LUSE devices are configured using the LUN Expansion (LUSE) feature. A LUSE device can be from 2 to 36 times larger than a fixed-size OPEN‑x LU. LUSE devices are designated as OPEN‑x* n, where x is the LU type and 2 < n < 36. For example, a LUSE device created by combining 10 OPEN‑3 LUs is designated as an OPEN‑3*10 device. LUSE lets the host access the data stored on the storage system using fewer LU numbers.

Note: LUSE devices are supported only on VSP and HUS VM storage systems.

VLL LUSE devices

(OPEN-x*n VLL)

Combined LUs composed of multiple VLL devices. VLL LUSE devices are configured first using the Virtual LUN feature to create custom‑size devices and then using the LUSE feature to combine the VLL devices. You can combine from 2 to 36 VLL devices into one VLL LUSE device. For example, an OPEN‑3 LUSE volume created from 10 OPEN‑3 VLL volumes is designated as an OPEN‑3*10 VLL device (product name OPEN‑3*10‑CVS).
FX devices

(3390 3A/B/C, OPEN-x FXoto)

The Hitachi Cross-OS File Exchange (FX) feature allows you to share data across mainframe and open-systems platforms using special multiplatform volumes called FX devices. FX devices are installed and accessed as raw devices (not SCSI disk devices). Windows hosts must use FX to access the FX devices as raw devices (no file system, no mount operation).

The 3390‑3B devices are write‑protected from Windows host access. The RAID storage system rejects all Windows host write operations (including FC adapters) for 3390‑3B devices.

The 3390‑3A/C and OPEN-x FXoto devices are not write‑protected for Windows host access. Do not execute any write operations on these devices. Do not create a partition or file system on these devices. This will overwrite data on the FX device and prevent the Cross-OS File Exchange software from accessing the device.

The VLL feature can be applied to FX devices for maximum flexibility in volume size.

The following table lists the specifications for the LDEVs on the RAID storage systems. The sector size for the devices is 512 bytes.

Device type

(Note 1)

Category

(Note 2)

Product name

(Note 3)

Number of blocks

(512 B/blk)

Number of cylinders Number of heads Number of sectors per track Capacity (MB)

(Note 4)

OPEN-3 SCSI disk OPEN-3 4806720 3338 15 96 7007
OPEN-8 SCSI disk OPEN-8 14351040 9966 15 96 2347
OPEN-9 SCSI disk OPEN-9 14423040 10016 15 96 7042
OPEN-E SCSI disk OPEN-E 28452960 19759 15 96 13893
OPEN-L SCSI disk OPEN-L 71192160 49439 15 96 34761
OPEN-3*n SCSI disk OPEN-3*n 4806720*n 3338*n 15 96 2347*n
OPEN-8*n SCSI disk OPEN-8*n 14351040*n 9966*n 15 96 7007*n
OPEN-9*n SCSI disk OPEN-9*n 14423040*n 10016*n 15 96 7042*n
OPEN-E*n SCSI disk OPEN-E*n 28452960*n 19759*n 15 96 13893*n
OPEN-L*n SCSI disk OPEN-L*n 71192160*n 49439*n 15 96 34761*n
OPEN-3VLL SCSI disk OPEN-3 CVS (Note 5) (Note 6) 15 96 (Note 7)
OPEN-8 VLL SCSI disk OPEN-8 CVS (Note 5) (Note 6) 15 96 (Note 7)
OPEN-9 VLL SCSI disk OPEN-9 CVS (Note 5) (Note 6) 15 96 (Note 7)
OPEN-E VLL SCSI disk OPEN-E CVS (Note 5) (Note 6) 15 96 (Note 7)
OPEN-V VLL SCSI disk OPEN-V (Note 5) (Note 6) 15 128 (Note 7)
OPEN-3*n VLL SCSI disk OPEN-3*n CVS (Note 5) (Note 6) 15 96 (Note 7)
OPEN-8*n VLL SCSI disk OPEN-8*n CVS (Note 5) (Note 6) 15 96 (Note 7)
OPEN-9*n VLL SCSI disk OPEN-9*n CVS (Note 5) (Note 6) 15 96 (Note 7)
OPEN-E*n VLL SCSI disk OPEN-E*n CVS (Note 5) (Note 6) 15 96 (Note 7)
OPEN-V*n VLL SCSI disk OPEN-V*n (Note 5) (Note 6) 15 128 (Note 7)
3390-3A FX otm/mto 3390-3A 5820300 3345 15 116 2844
3390-3B FX mto 3390-3B 5816820 3343 15 116 2844
3390-3C FX otm OP-C-3390-3C 5820300 3345 15 116 2844
FXOPEN-3 FX oto OPEN-3 4806720 3338 15 96 2347
3390-3A VLL FX otm/mto 3390-3A-CVS (Note 5) (Note 6) 15 116 (Note 7)
3390-3B VLL FX mto 3390-3B-CVS (Note 5) (Note 6) 15 116 (Note 7)
3390-3C VLL FX otm OP-C-3390-3C-CVS (Note 5) (Note 6) 15 116 (Note 7)
FX OPEN-3 VLL FX oto OPEN-3-CVS (Note 5) (Note 6) 15 96 (Note 7)
Notes:
  1. The availability of specific device types depends on the storage system model and the level of microcode installed on the storage system.
  2. The category of a device (SCSI disk or Cross-OS File Exchange) determines its volume usage. SCSI disk devices (for example, OPEN-V) are usually formatted with file systems but can also be used as raw devices (for example, some applications use raw devices).
  3. The product name for Virtual LUN devices is OPEN-x CVS, where CVS = custom volume size. The command device (used for Command Control Interface operations) is distinguished by "–CM" on the product name (for example, OPEN-V-CM).
  4. This capacity is the maximum size that can be entered. The device capacity can sometimes be changed by the BIOS or host adapter. Also, different capacities may be due to variations such as 1 MB = 10002 bytes or 10242 bytes.
  5. The number of blocks for a Virtual LVI/LUN volume is calculated as follows:
    # of blocks = (# of data cylinders) × (# of heads) × (# of sectors per track)

    The number of sectors per track is 128 for OPEN-V and 96 for the other emulation types. Example for an OPEN-3 VLL volume with capacity = 37 MB:

    # of blocks = (53 cylinders – see Note 3) × (15 heads) × (96 sectors per track) = 76320
  6. The number of data cylinders for a Virtual LVI/LUN volume is calculated as follows ( ceil (value) means that the value should be rounded up to the next integer):
    • Number of data cylinders for OPEN-x VLL volume (except for OPEN-V)
      # of cylinders =  ceil((capacity (MB) × 1024/720 )

      Example: For OPEN-3 VLL volume with capacity = 37 MB:

      # of cylinders = ceil(37 × 1024/720) = ceil(52.62) = 53 cylinders
    • Number of data cylinders for an OPEN-V VLL volume
      # of cylinders = ceil((capacity (MB) specified by user) × 16/15)

      Example: For OPEN-V VLL volume with capacity = 50 MB:

      # of cylinders = ceil(50 × 16/15) = ceil(53.33) = 54 cylinders
  7. The size of an OPEN-x VLL volume is specified by capacity in MB, not number of cylinders. The size of an OPEN-V VLL volume can be specified by capacity in MB or number of cylinders.