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perf(storages): an ISO uploads to an SSH compute without waiting for each write

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Each 32 MiB chunk went out as 1024 SFTP writes, each waiting for its
answer: 19 MiB/s on a gigabit LAN, ~1.9 s per chunk with the SSH session.
The writes now go out without waiting and their answers are read as they
come and at the end: ~0.53 s per chunk, the same file (checked by sha256).

paramiko's own pipelined writes (set_pipelined) drop the errors in their
answers, so a full disk would leave a short ISO behind a successful
upload. Each write is registered to its file instead, the way paramiko
does for prefetched reads: every answer, in any order, reaches the file
and an error is raised as soon as one is read.
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catborise 2026-10-09 13:15:55 +03:00
parent 24231813d7
commit a87fbf739f
4 changed files with 136 additions and 5 deletions
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@ -536,6 +536,7 @@ A rollback leaves the clone on a detached HEAD at the restored commit; the updat
- A disk can be grown while its VM runs or is paused, not only when it is shut off.
- A host's CPU graph shows the average since its previous point (normally 5 s) instead of a 1 s sample taken while a worker waits.
- A VM's stats are polled every 5 s like the host graph, the first point as soon as the tab opens; each point is the average since the previous one, disk rates in MB/s (they were MiB/s labelled Mb/s); a counter the host does not report shows a gap instead of 0.
- An ISO uploads to an SSH compute about 3.5 times faster (SFTP writes no longer wait for each 32 KiB); a failed write still fails the upload.
- A running VM without a guest agent shows the IPv4 address the host learned by ARP (the lookup always failed before).
- After a live migration the VM's NVRAM file is deleted on the source, when it is in libvirt's `/var/lib/libvirt/qemu/nvram` and the destination does not share that directory (a VM created there later with the same name would start with those UEFI variables).
- gstfsd finds the guest's operating system the way libguestfs inspects it, so a root on LVM works, and it always answers (an error when it finds no or several operating systems). Update `/usr/local/bin/gstfsd` on every compute (see [Adding a Compute Node](#adding-a-compute-node), step 3).