- Disk defragment vm esxi 6.5 full size#
- Disk defragment vm esxi 6.5 update#
- Disk defragment vm esxi 6.5 driver#
- Disk defragment vm esxi 6.5 manual#
- Disk defragment vm esxi 6.5 windows 7#
I was playing with guest TRIM/UNMAP the other day and looked at new shiny virtual NVMe controller.
Disk defragment vm esxi 6.5 manual#
Delete reclaims space, (ironically) manual defrag frees space, also sdelete zero successfully reclaims space.
Disk defragment vm esxi 6.5 windows 7#
The nice thing is that it works with Windows 7 and Windows 2008 R2! Remember that they don’t support SCSI UNMAP. It’s within the margin of error, in real life it’s basically the same as PVSCSI. It seems to be VERY slightly faster and have VERY slightly lower CPU overhead. Disk defragment vm esxi 6.5 update#
Will update if I remember to (or get feedback from VMware).
One VMFS6 locking issue that may or not be related to vNVME. Newer kernels (4.9+ ?) have configuration device to rescan, older require VM reboot Disk defragment vm esxi 6.5 driver#
When increasing VMDK sizes, Linux NVME driver doesn’t notice namespace resize. “CRAZY FAST, CRAZY LOW LATENCY!!!” you scream? Well fabrics and transport layers still may have hickups and tolerating transient issues might be better than being broken. With VMTools, only SCSI gets increase to 180s so you might want to manually increase nvme module timeout just in case. 
Linux NVMe controller has a default timeout of 30s. Ugly warning/errors is Linux kernel log if Discard is blocked (snapshot create/commit) – harmless. Author DZ Posted on Categories Posts Tags UNMAP, VMware, vSphere, Windows Leave a comment on vSphere 6.5 guest UNMAP may cause VM I/O latency spikes – fixed in update 1 vSphere 6.5 virtual NVMe does not support TRIM/UNMAP/Deallocate I’m not sure what’s going on but perhaps ESXi is doing some kind of defrag operation in VMDK…? And yeah, doing a defrag (you can do it manually form command line in Windows 2012+) and then UNMAP helps too. On some more internally fragmented huge (multi-TB) VMs, particularly those with 4K clusters, space usage seems to reduce slowly over days or weeks. I’ve noticed that for some VM’s, you don’t space back immediately. Sure, it might be a bit slower during UNMAP run but it’s basically invisible for most workloads. I’ve been running Update 1 since pretty much release date and UNMAP works great! No particular performance hit. In the end VMware support confirmed the issue with expected release of 6.5 Update 1 at the end of July. Veeam’s (or Anton Gostev’s) newsletter mentioned a similar issue just as I came across this issue again in a new vSphere cluster. For example, a 9TB thick file server took 3 days to shrink to 5TB. On some larger VMs with possible alignment issues, reclamation takes several days though. PS! Savings were great, on some systems nearly 100% from VMFS perspective. As I said, I cannot investigate it any further but I’ll update the post if I ever hear anything. Might be the IBM v7000 G2 SAN that goes crazy. I’m not sure where the problem is and I can’t look into it anymore. After several days, I converted VMs back to thick and issues disappeared. It also seems to affect other surrounding VMs, just not as badly. I/O latency just spikes to 400ms for minutes for no apparent reason. Initial retrim caused transient I/O slowdown in VM but the issue kept reappearing randomly. I converted some VMs to thin and upgraded VM hardware version to 13 to test out savings. Disk defragment vm esxi 6.5 full size#
Author DZ Posted on Categories Posts Tags ESXi, UNMAP, VMware, vSphere Leave a comment on Running UNMAP on snapshotted VMware hardware 11+ thin VMs may cause them to inflate to full size vSphere 6.5 guest UNMAP may cause VM I/O latency spikes – fixed in update 1 I haven’t seen this anywhere else but I guess I’ll do a reproducable PoC, contact VMware support and do an update.
You can retrim after snapshot commit and it drops down to normal size quickly (minutes). While I could disable automatic retrim (bad with lots of small file operations, normal UNMAP isn’t very effective on them due to alignment issues) or UNMAP (even worse), it’s an acceptable risk for now if you keep enough free space on datastore to absorb inflation of the biggest VM. Also it tends to happen during backup windows that keep snapshots open for quite a while (usually at night, terrible). I’ve seen it happen quite a few times and it’s really annoying if you for some historical reason have tons of free space on drives (for example NTFS dedup was enabled long after deployment) and may even cause datastores to become full (needless to say, really bad). It also results in really long commit times. If you snapshot VM and run UNMAP (for example retrim from defrag utility), VM may (not always) inflate to full size during snapshot commit.
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