Good post on reddit from /r/kcbnac:
As with many things in IT – It Depends.
SD card is identified by ESXi/vSphere as being flash-based media, so it won’t log to it – you’d need another volume somewhere for logs and dumps to go (not a bad idea anyway; but then if THAT goes down you have no logs – which isn’t helpful when the Vendor Blame Game begins)
SD is cheaper in a large cluster, provided you can meet the above logging requirement. (Saved ~$10k on 8 blade hosts buying SD cards instead of a RAID-1 mirror’d pair of drives for each; and nothing big/fancy either – would’ve been 300GB 10K SAS in Gen8 HP blades)
HDD/SSD gives you room on not-shared-storage to put some critical VMs in a pinch, or just ones that can’t live on the SAN. (I’m picturing the VMs that assist the SAN that shouldn’t live on the arrays they support; or extra space in a shuffle)
HDD uses more power, generating more heat. Another moving part.
Its a choice of tradeoffs, as usual.
Failover using Vmware Site Replication Manager (SRM) 5.5 And Dell Equallogic Storage Replication Adapter (SRA )
Datacenter Site A:
There is a problem where we know we have power outages coming or we have one currently:
In this example: volumesiteA is volume with vms that needs to be failed over to recovery site B.
Recovery to start actual failover to Datacenter Site B:
A warning will pop up:
The difference between planned migration and disaster recovery is that if there are errors the recovery will stop if its planned.
In a true DR situation where site A is down use forced recovery.
One we hit start the recovery begins.
On the Equallogic side you can see that the volume status is set to offline
On recovery site B you will see a new volume appear
Once recovery is complete you can test your migrated servers
If we go back to the failed over datastore on site B, we will see
The volume is not replicated
You may get “amount of in-use snapshot reserve exceeds the warning limit”
Go over to the snapshot windows and delete some snapshots or increase space dedicated to snapshots
If we look at the volume on site A
We will see that the volume is still has a replication job to site B, though it will fail (notice the cancel)
Debate going over on reddit: https://www.reddit.com/r/sysadmin/comments/3av7li/nimble_vs_tegile
Of interest from SquizzOC:
I’ve got over 50 projects closed with Tegile and here’s why:
- Hybrid or All flash
- Multi-Protocol: iSCSI, FC, CIFS, NFS, SMB all in the same array.
- Inline DeDupe and Compression
- Zero licensing costs (I don’t believe this applies to Nimble either)
Their end of quarter is July so if you plan on purchasing in the near future, cutting a PO by mid July will net you the best cost. I’m seeing deals approved with an additional 20% discount above and beyond their normal killer pricing. Last Nimble vs. Tegile project I quoted:
- Tegile: 107k
- Nimble: 140k
Tegile came in with a more powerful array as well. If you aren’t working with a VAR, Ping me and I can guide you sir. I prefer to have the business go through me of course, but if I can help put another Tegile array in a home I’m happy 🙂
Ssukin also echoed that result: with Tegile being the top contender though he was posting reviews from his employer’s site IT centralstation .
VSA : vSphere Storage Appliance
What is it?
The precursor to VSAN, the VSA enabled hosts to have software based shared storage without the need for a dedicated storage platform .
“this appliance is aimed at our SMB (Small and Mid-size Business) customers who may not be in a position to purchase a physical SAN or NAS array for their virtual infrastructure, and as a result, these customers do not have shared storage”
As of April 1, 2014. all VSA has entered end of life and can no longer be purchased.
How does it work?
The software would divide up the disk allocation in such a way that a volume from one host is mirrored on another.
The selling point is that you can use a minimal set of hardware, or even an existing one, to take advantage of the great features vSphere offered while having to forgo unneeded expenditures that a company ,may not be willing to make.
A company can use high availability and DRS with a smaller investment rather than using tens of thousands to potentially hundreds of thousands on shared storage.
VSAN is a MUCH better product than VSA.
Where VSA was aimed at small to medium business, VSAN is focused on the enterprise market, moving away from what Duncan Epping likes to call “San Huggers”.
VSAN is built into the vSphere kernel, it has SSD caching, scalable and ready for the prime time.
Here is a nice comparison thanks to vSphere blog
Vmware ended a product line that, while an interesting concept at the time, has fulfilled its need. Its features have been placed into the kernel itself, integrating the best, while adding new fatures. So VSA isnt gone in a way, just renamed. Like a lot of other Vmware products.