Deploying a drive on a system writes metadata to the drive that is not compatible between ME Series storage systems. For this reason, ME4 Series storage systems do not support drives that have already been deployed either internally on an ME5 Series base system or on an expansion enclosure that has been used on an ME5 Series storage system. The reverse is also true: a drive that has been deployed on an ME4 Series storage system (internally or on an expansion) cannot be used in an ME5 Series system.
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Maximum number of host servers that a single storage system can connect to with one RAID controller module installed
| 4
| 256
| 256
|
Maximum number of host servers that a single storage system can connect to with two RAID controller modules installed
| 8 (4, if using high availability or redundancy)
| 256
| 256
|
Maximum number of Dell 12 Gbps SAS HBA cards that are supported in a single host server that is attached to single storage system. Dell recommends that you use two Dell 12 Gb SAS HBA cards for all redundant cabling configurations.
| 2 (each card has two ports)
| N/A
| N/A
|
Unused ports on a Dell 12 Gbps SAS HBA card already connected to an ME4 SAS storage system cannot connect to another device (such as a tape drive or other model storage system)
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | N/A
| N/A
|
Maximum number ME4 Series storage system to which a host server can connect
| 2 (HA)
| 4
| 4
|
A hot spare for a disk group must be a drive of equal or greater size than any of the member disks
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
On Linux systems, Device Mapper multipath is required for multipath support
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Coexistence of several Linux multipath drivers is not supported. For an ME4 series storage system with Linux host servers, only the Linux Device Mapper failover driver is supported
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Virtual disks on ME4 Series storage system cannot be used for booting
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Disk Groups can be migrated between a ME4 Series storage systems by following the appropriate disk pool migration procedure
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Maximum SSD cache size that is allowed is two SSDs
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
All iSCSI host ports on a controller must have the same port speed
| N/A
| ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Maximum 12 Gbps SAS cable length that is supported is 4 m
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
iSCSI network rules:
- If the iSCSI initiators are connected to ME4 Series storage systems through the network switches, ensure that your switches support IEEE 802.3x flow control, and the flow control is enabled for both sending and receiving on all switch ports and server NIC ports
- If you do not enable the flow control, your iSCSI storage may experience degradation of the I/O performance
- In addition to enabling the Ethernet IEEE 802.3x flow control, Dell recommends that you disable unicast broadcast storm control on the switch ports that are connected to the iSCSI initiators and target storage systems. Dell also recommends turning on the "PortFast" mode of the spanning tree protocol (STP) on the switch ports that are connected to the iSCSI initiators and target system
- Turning on the PortFast mode is different from turning off the whole operation of STP on the switch. With PortFast on, STP is still enabled on the switch ports. Turning off STP may affect the entire network and can leave the network vulnerable to physical topology loops.
| N/A
| ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
For optimal I/O performance, avoid having more than one iSCSI session originating from one host iSCSI port to the same controller. Ideally, the iSCSI host NIC must connect to only one iSCSI target port on the storage subsystem
| N/A
| ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
The FC can connect at either or 8 Gbps and 16 Gbps, however 16 Gbps is recommended
| N/A
| N/A
| ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
The 10GBaseT iSCSI controller module can auto-negotiate to 1 Gbps. The CNC requires a 10 Gbps connection
| N/A
| ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Remote replication is not supported when the replication connection is directly connected. It must be in a switch topology
| N/A
| ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Replication within iSCSI topology between ME4 series storage systems is supported regardless of connection speed. Replication between iSCSI and FC topology is not supported
| N/A
| ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | N/A
|
Replication within FC topology between ME4 storage systems is supported regardless of connection speed. Replication between iSCSI and FC topology is not supported
| N/A
| N/A
| ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Online Drive firmware upgrade is not supported and might cause hosts to lose connectivity with the storage system
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
When using drives that are 6 TB or larger, it is recommended to use either a RAID 6 Disk Group or an ADAPT Disk Pool. Due to the increased amount of time that is taken to reconstruct and copy-back, the chances for a second drive failure increases on either a RAID 1/10 or a RAID 5 Disk Group
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Data Assurance capable drives are supported in the storage system, however the Data Assurance feature is not available for these storage systems
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
To create an NRAID, RAID 0, or RAID 3 (linear-only) disk group, you must use the CLI. For more information, see the
Dell EMC PowerVault ME4 Series Storage System CLI Guide.
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Disk groups and pools
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Minimum and maximum disks per virtual disk group:
- NRAID (non-RAID):1/1 (read cache only)
- RAID 0: 2/2 (read cache only)
- RAID 1: 2/2
- RAID 3 Not supported
- RAID 5: 3/16
- RAID 6: 4/16
- RAID 10: 4/16
- RAID 50: Not supported
- ADAPT: 12/128
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Minimum and maximum disks per linear disk group:
- NRAID (non-RAID):1/1
- RAID 0: 2/16
- RAID 1: 2/2
- RAID 3: 3/16
- RAID 5: 3/16
- RAID 6: 4/16
- RAID 10: 4/16
- RAID 50: 6/32
- ADAPT: 12/128
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Volumes, Initiators, hosts, and mapping:
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Supported FC/iSCSI module host-port configurations per controller module:
- 4 ports FC
- 4 ports iSCSI
- 2 ports FC and 2 port iSCSI
| N/A
| N/A
| ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Virtual volume snapshots:
- Maximum snapshots per pool = 512
- Maximum base volumes per system = 1024
- Maximum base snapshots per volume
- 254 in the volume snapshot tree with a license and the large pools feature disabled in the CLI
- 8 in the volume snapshot tree with the large pools feature enabled in the CLI
- Maximum mappable snapshots per system = 1024
NOTE Active snapshots and replications use a substantial amount of the reserved space and undesired effects might occur if the reserved space is completely consumed. Use the CLI command
show snapshot-space to monitor space usage.
| ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Virtual volume replication:
- Maximum number of peer connections per system = 4
- Maximum number of replicated volumes per system = 32
- Maximum number of replicated sets for a volume = 1
- Maximum number of volumes for a replicated volume group = 16, if no other volumes belong to a replication set
- Minimum replication frequency that can be scheduled = 1
| N/A
| ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Maximum SCSI reservations
- Per controller module = 1024
- Per LUN = 1
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Maximum SCSI registrations for virtual storage
- Per system: 32768
- Per LUN: 4096
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
Maximum SCSI registrations for linear storage
- Per system: 32768
- Per FC LUN: 128
- Per iSCSI LUN: 85-128 depending on IQN length
- Per SAS LUN: 128
| ![Applicable to SAS](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to 10GBaseT iSCSI](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) | ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |
- Presenting the same volume (LUN) through FC AND iSCSI to one or more hosts or host groups is not supported.
| N/A
| N/A
| ![Applicable to CNC](https://dl.dell.com/content/guides/public/Html/me4_series_sm_pub/images/GUID-0EAC296D-41E2-495F-9AF4-D20066138DE6-low.jpg) |