fix(snapshots): Fixup for #3624. Shadow copy seems to extend time for snapshots.

[aaron-kasten]

PR #3543 seems to put IO resource pressure on the system. Enough to cause TestServerScheduling to fail due to snapshot latencies - which, in turn, causes Windows tests to fail as a flake.

This PR embodies the fix suggested by @jkowalski.

This fix also fixes the SIGFAULTS caused by use of the -race flag, which points to a possible problem in dependent library.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (b057b0b) 75.86% compared to head (3810e9f) 75.84%.

❗ Current head 3810e9f differs from pull request most recent head 61b4232. Consider uploading reports for the commit 61b4232 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3625      +/-   ##
==========================================
- Coverage   75.86%   75.84%   -0.03%     
==========================================
  Files         470      470              
  Lines       37301    37301              
==========================================
- Hits        28300    28291       -9     
- Misses       7073     7079       +6     
- Partials     1928     1931       +3     

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[Shrekster]

@aaron-kasten , how about keeping the test enabled with a simple change of enabling the VSS policy just for the test and keeping it disabled by default otherwise as you already did:

diff --git a/cli/command_policy_set_os_snapshot_test.go b/cli/command_policy_set_os_snapshot_test.go
index 6165a09d..ac8e86f7 100644
--- a/cli/command_policy_set_os_snapshot_test.go
+++ b/cli/command_policy_set_os_snapshot_test.go
@@ -10,15 +10,19 @@
 )

 func TestSetOSSnapshotPolicy(t *testing.T) {
-       t.Skip("See ticket https://github.com/kopia/kopia/issues/3624")
        e := testenv.NewCLITest(t, testenv.RepoFormatNotImportant, testenv.NewInProcRunner(t))
-
        defer e.RunAndExpectSuccess(t, "repo", "disconnect")

        e.RunAndExpectSuccess(t, "repo", "create", "filesystem", "--path", e.RepoDir)

        lines := e.RunAndExpectSuccess(t, "policy", "show", "--global")
        lines = compressSpaces(lines)
+       require.Contains(t, lines, " Volume Shadow Copy: never (defined for this target)")
+
+       e.RunAndExpectSuccess(t, "policy", "set", "--global", "--enable-volume-shadow-copy=when-available")
+
+       lines = e.RunAndExpectSuccess(t, "policy", "show", "--global")
+       lines = compressSpaces(lines)
        require.Contains(t, lines, " Volume Shadow Copy: when-available (defined for this target)")

        // make some directory we'll be setting policy on

[aaron-kasten]

@aaron-kasten , how about keeping the test enabled with a simple change of enabling the VSS policy just for the test and keeping it disabled by default otherwise as you already did:

diff --git a/cli/command_policy_set_os_snapshot_test.go b/cli/command_policy_set_os_snapshot_test.go
index 6165a09d..ac8e86f7 100644
--- a/cli/command_policy_set_os_snapshot_test.go
+++ b/cli/command_policy_set_os_snapshot_test.go
@@ -10,15 +10,19 @@
 )

 func TestSetOSSnapshotPolicy(t *testing.T) {
-       t.Skip("See ticket https://github.com/kopia/kopia/issues/3624")
        e := testenv.NewCLITest(t, testenv.RepoFormatNotImportant, testenv.NewInProcRunner(t))
-
        defer e.RunAndExpectSuccess(t, "repo", "disconnect")

        e.RunAndExpectSuccess(t, "repo", "create", "filesystem", "--path", e.RepoDir)

        lines := e.RunAndExpectSuccess(t, "policy", "show", "--global")
        lines = compressSpaces(lines)
+       require.Contains(t, lines, " Volume Shadow Copy: never (defined for this target)")
+
+       e.RunAndExpectSuccess(t, "policy", "set", "--global", "--enable-volume-shadow-copy=when-available")
+
+       lines = e.RunAndExpectSuccess(t, "policy", "show", "--global")
+       lines = compressSpaces(lines)
        require.Contains(t, lines, " Volume Shadow Copy: when-available (defined for this target)")

        // make some directory we'll be setting policy on

@Shrekster that looks great. As long as this PR's test passes and other PRs are not blocked. I'm not so versed in VSS as to be able to make a judgement on the quality of the fix beyond that.

[Shrekster]

LGTM; merge as tests pass