storage best practices
TRANSCRIPT
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Storage Best Practices
Maor LipchukMarch 2015Senior Software Engineer @ RHEVRed [email protected]
Irc.oftc.net server on #ovirt channel
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Agenda
● oVirt Storage Domains Overview
● Manual Tiering
● Volume Types
● Single Disk Snapshot
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Storage Domains Types
File Storage Domains
● NFS
● Gluster
● POSIX-Compliant FS
● Local
Block Storage Domains
● Fibre Channel
● ISCSI
● Ceph (oVirt 3.6)
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Manual Tiering
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Manual Tiering
● Introduced in oVirt 3.4
● Maintain different types of Storage Domains in a Data Center
● Feature page: http://www.ovirt.org/Features/Mixed_Types_Data_Center
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Manual Tiering
NFS
iSCSI
FCP
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Manual Tiering
oVirt setup - Manual Tiering
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Manual Tiering - iSCSI
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Manual Tiering - Fibre Channel
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Manual Tiering - NFS
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Manual Tiering
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Manual Tiering - Choose The best Storage
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Manual Tiering
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Volume Types
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Volume Types
● Allocation policy – How should VDSM allocate the storage
● Preallocated - VDSM will try to allocate the space right away
● Sparse/thin provision - Space will be allocated for the volume as needed
● Volume format - How the bits are written to the underlying volume
● RAW - simple raw access
● QCOW2 - file format for disk image files used by QEMU
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Volume Types – Allocation Policy
● Preallocation● improve performance for I/O operations● Wasteful regarding disk space
● Sparse/Thin provisioning● Saving on disk space,● storage is allocated as data is being written to
the file.● Might cause defragmentation ● performance implications
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Volume Types – Volume Format
● QCOW3 (oVirt 3.6)
● QCOW2 - QEMU Copy On Write● File format for disk image files used by QEMU
● The image only represents changes made to an underlying disk image
● Image can contain multiple snapshots of the images history
● Only QCOW2 volumes can be snapshots themselves.
● RAW - Simple raw access
● Has better performance then QCOW2
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Volume Types – Snapshot With QCOW2
SnapshotLV
Base VolumeLV
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Volume Types – Storage Domains
● File Storage Domains● Files thinly provisioned by design● "Preallocation" is achieved by writing zeros
● Block Storage Domains● Thin provisioning - (Transparent to Vdsm) requires defining
the LUNs as sparse on the storage array● Preallocated volumes are simply LVs created with the same
size as the virtual disk
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Volume Types
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Single Disk Snapshot
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Single Disk Snapshot
● Introduced in oVirt 3.4
● Capacity planning & sizing
● Customization of snapshots with regarding to
VM configuration
Disks
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Single Disk Snapshot - LVM
● LVM - logical volume manager for the Linux kernel
● Simple block-level schema for creating virtual block devices
● Manages disk drives and similar mass-storage devices
● Supports up to 500 LVs
● Every disk and a snapshot is a LV
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Single Disk Snapshot – LVM Architecture
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Single Disk Snapshot – oVirt
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Single Disk Snapshot – oVirt
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Questions?
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THANK YOU !
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